init: remove the need for a dummy device pointer in SYS_INIT functions

The init infrastructure, found in `init.h`, is currently used by:

- `SYS_INIT`: to call functions before `main`
- `DEVICE_*`: to initialize devices

They are all sorted according to an initialization level + a priority.
`SYS_INIT` calls are really orthogonal to devices, however, the required
function signature requires a `const struct device *dev` as a first
argument. The only reason for that is because the same init machinery is
used by devices, so we have something like:

```c
struct init_entry {
	int (*init)(const struct device *dev);
	/* only set by DEVICE_*, otherwise NULL */
	const struct device *dev;
}
```

As a result, we end up with such weird/ugly pattern:

```c
static int my_init(const struct device *dev)
{
	/* always NULL! add ARG_UNUSED to avoid compiler warning */
	ARG_UNUSED(dev);
	...
}
```

This is really a result of poor internals isolation. This patch proposes
a to make init entries more flexible so that they can accept sytem
initialization calls like this:

```c
static int my_init(void)
{
	...
}
```

This is achieved using a union:

```c
union init_function {
	/* for SYS_INIT, used when init_entry.dev == NULL */
	int (*sys)(void);
	/* for DEVICE*, used when init_entry.dev != NULL */
	int (*dev)(const struct device *dev);
};

struct init_entry {
	/* stores init function (either for SYS_INIT or DEVICE*)
	union init_function init_fn;
	/* stores device pointer for DEVICE*, NULL for SYS_INIT. Allows
	 * to know which union entry to call.
	 */
	const struct device *dev;
}
```

This solution **does not increase ROM usage**, and allows to offer clean
public APIs for both SYS_INIT and DEVICE*. Note that however, init
machinery keeps a coupling with devices.

**NOTE**: This is a breaking change! All `SYS_INIT` functions will need
to be converted to the new signature. See the script offered in the
following commit.

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>

init: convert SYS_INIT functions to the new signature

Conversion scripted using scripts/utils/migrate_sys_init.py.

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>

manifest: update projects for SYS_INIT changes

Update modules with updated SYS_INIT calls:

- hal_ti
- lvgl
- sof
- TraceRecorderSource

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>

tests: devicetree: devices: adjust test

Adjust test according to the recently introduced SYS_INIT
infrastructure.

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>

tests: kernel: threads: adjust SYS_INIT call

Adjust to the new signature: int (*init_fn)(void);

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>

soc/arm/ti_simplelink/cc13x2_cc26x2/power.c

@@ -136,11 +136,10 @@ __weak void pm_state_exit_post_ops(enum pm_state state, uint8_t substate_id)
 #endif /* CONFIG_PM */
 
 /* Initialize TI Power module */
-static int power_initialize(const struct device *dev)
+static int power_initialize(void)
 {
 	unsigned int ret;
 
-	ARG_UNUSED(dev);
 
 	ret = irq_lock();
 	Power_init();
@@ -154,7 +153,7 @@ static int power_initialize(const struct device *dev)
  * This needs to be called during POST_KERNEL in order for "Booting Zephyr"
  * message to show up
  */
-static int unlatch_pins(const struct device *dev)
+static int unlatch_pins(void)
 {
 	/* Get the reason for reset. */
 	uint32_t rSrc = SysCtrlResetSourceGet();

soc/arm/ti_simplelink/cc13x2_cc26x2/soc.c

@@ -8,9 +8,8 @@
 
 #include <driverlib/setup.h>
 
-static int ti_cc13x2_cc26x2_init(const struct device *dev)
+static int ti_cc13x2_cc26x2_init(void)
 {
-	ARG_UNUSED(dev);
 
 	/* Performs necessary trim of the device. */
 	SetupTrimDevice();

soc/arm/ti_simplelink/cc13x2x7_cc26x2x7/power.c

@@ -136,11 +136,10 @@ __weak void pm_state_exit_post_ops(enum pm_state state, uint8_t substate_id)
 #endif /* CONFIG_PM */
 
 /* Initialize TI Power module */
-static int power_initialize(const struct device *dev)
+static int power_initialize(void)
 {
 	unsigned int ret;
 
-	ARG_UNUSED(dev);
 
 	ret = irq_lock();
 	Power_init();
@@ -154,7 +153,7 @@ static int power_initialize(const struct device *dev)
  * This needs to be called during POST_KERNEL in order for "Booting Zephyr"
  * message to show up
  */
-static int unlatch_pins(const struct device *dev)
+static int unlatch_pins(void)
 {
 	/* Get the reason for reset. */
 	uint32_t rSrc = SysCtrlResetSourceGet();

soc/arm/ti_simplelink/cc13x2x7_cc26x2x7/soc.c

@@ -8,9 +8,8 @@
 
 #include <driverlib/setup.h>
 
-static int ti_cc13x2_cc26x2_init(const struct device *dev)
+static int ti_cc13x2_cc26x2_init(void)
 {
-	ARG_UNUSED(dev);
 
 	/* Performs necessary trim of the device. */
 	SetupTrimDevice();

soc/arm/ti_simplelink/cc32xx/soc.c

@@ -18,9 +18,8 @@ void sys_arch_reboot(int type)
 	MAP_PRCMMCUReset(!!type);
 }
 
-static int ti_cc32xx_init(const struct device *arg)
+static int ti_cc32xx_init(void)
 {
-	ARG_UNUSED(arg);
 
 	/* Note: This function also performs CC3220 Initialization */
 	MAP_PRCMCC3200MCUInit();

soc/arm/ti_simplelink/msp432p4xx/soc.c

@@ -9,9 +9,8 @@
 #include <zephyr/init.h>
 #include <soc.h>
 
-static int ti_msp432p4xx_init(const struct device *arg)
+static int ti_msp432p4xx_init(void)
 {
-	ARG_UNUSED(arg);
 
 	SystemInit();