boards: st: fix STM32G4 boards DTS files coding style

Fix board DTS coding style issues to prevent they spread when a	new
board is introduced and used this DTS as example start point.

Issues addressed from Zephyr devicetree style guidelines [1]:
- Insert a single empty line to separate nodes at the same hierarchy level.

By the way, also correct indentation in node stm32_lp_tick_source of
b_g474e_dpow1.dts.

No functional change.

Link: https://docs.zephyrproject.org/latest/contribute/style/devicetree.html [1]
Signed-off-by: Etienne Carriere <etienne.carriere@st.com>

boards/st/b_g474e_dpow1/b_g474e_dpow1.dts

@@ -22,18 +22,22 @@
 
 	leds {
 		compatible = "gpio-leds";
+
 		blue_led_2: led2 {
 			gpios = <&gpioa 15 GPIO_ACTIVE_HIGH>;
 			label = "LED_DOWN_BLUE";
 		};
+
 		orange_led_3: led3 {
 			gpios = <&gpiob 1 GPIO_ACTIVE_HIGH>;
 			label = "LED_LEFT_ORANGE";
 		};
+
 		green_led_4: led4 {
 			gpios = <&gpiob 7 GPIO_ACTIVE_HIGH>;
 			label = "LED_RIGHT_GREEN";
 		};
+
 		red_led_5: led5 {
 			gpios = <&gpiob 5 GPIO_ACTIVE_HIGH>;
 			label = "LED_UP_RED";
@@ -42,26 +46,31 @@
 
 	gpio_keys {
 		compatible = "gpio-keys";
+
 		joystick_sel: button0 {
 			label = "JOYSTICK_SEL";
 			gpios = <&gpioc 13 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
 			zephyr,code = <INPUT_KEY_ENTER>;
 		};
+
 		joystick_left: button1 {
 			label = "JOYSTICK_LEFT";
 			gpios = <&gpioc 4 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
 			zephyr,code = <INPUT_KEY_LEFT>;
 		};
+
 		joystick_down: button2 {
 			label = "JOYSTICK_DOWN";
 			gpios = <&gpioc 5 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
 			zephyr,code = <INPUT_KEY_DOWN>;
 		};
+
 		joystick_right: button3 {
 			label = "JOYSTICK_RIGHT";
 			gpios = <&gpiob 2 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
 			zephyr,code = <INPUT_KEY_RIGHT>;
 		};
+
 		joystick_up: button4 {
 			label = "JOYSTICK_UP";
 			gpios = <&gpiob 10 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
@@ -97,7 +106,7 @@
 
 stm32_lp_tick_source: &lptim1 {
 	clocks = <&rcc STM32_CLOCK_BUS_APB1 0x80000000>,
-	<&rcc STM32_SRC_LSI LPTIM1_SEL(1)>;
+		 <&rcc STM32_SRC_LSI LPTIM1_SEL(1)>;
 	status = "okay";
 };
 

boards/st/nucleo_g431kb/nucleo_g431kb.dts

@@ -21,6 +21,7 @@
 
 	leds: leds {
 		compatible = "gpio-leds";
+
 		green_led: led_0 {
 			gpios = <&gpiob 8 GPIO_ACTIVE_HIGH>;
 			label = "User LD2";
@@ -102,7 +103,6 @@ stm32_lp_tick_source: &lptim1 {
 };
 
 &flash0 {
-
 	partitions {
 		compatible = "fixed-partitions";
 		#address-cells = <1>;

boards/st/nucleo_g431rb/nucleo_g431rb.dts

@@ -25,6 +25,7 @@
 
 	leds: leds {
 		compatible = "gpio-leds";
+
 		green_led: led_0 {
 			gpios = <&gpioa 5 GPIO_ACTIVE_HIGH>;
 			label = "User LD2";
@@ -41,6 +42,7 @@
 
 	gpio_keys {
 		compatible = "gpio-keys";
+
 		user_button: button {
 			label = "User";
 			gpios = <&gpioc 13 GPIO_ACTIVE_HIGH>;
@@ -163,7 +165,6 @@ stm32_lp_tick_source: &lptim1 {
 };
 
 &flash0 {
-
 	partitions {
 		compatible = "fixed-partitions";
 		#address-cells = <1>;
@@ -173,14 +174,17 @@ stm32_lp_tick_source: &lptim1 {
 			label = "mcuboot";
 			reg = <0x00000000 DT_SIZE_K(34)>;
 		};
+
 		slot0_partition: partition@8800 {
 			label = "image-0";
 			reg = <0x00008800 DT_SIZE_K(48)>;
 		};
+
 		slot1_partition: partition@14800 {
 			label = "image-1";
 			reg = <0x00014800 DT_SIZE_K(42)>;
 		};
+
 		/* Set 4Kb of storage at the end of the 128Kb of flash */
 		storage_partition: partition@1f000 {
 			label = "storage";

boards/st/nucleo_g474re/nucleo_g474re.dts

@@ -26,6 +26,7 @@
 
 	leds: leds {
 		compatible = "gpio-leds";
+
 		green_led: led_0 {
 			gpios = <&gpioa 5 GPIO_ACTIVE_HIGH>;
 			label = "User LD2";
@@ -42,6 +43,7 @@
 
 	gpio_keys {
 		compatible = "gpio-keys";
+
 		user_button: button {
 			label = "User";
 			gpios = <&gpioc 13 GPIO_ACTIVE_LOW>;
@@ -177,14 +179,17 @@ stm32_lp_tick_source: &lptim1 {
 			label = "mcuboot";
 			reg = <0x00000000 DT_SIZE_K(34)>;
 		};
+
 		slot0_partition: partition@8800 {
 			label = "image-0";
 			reg = <0x00008800 DT_SIZE_K(240)>;
 		};
+
 		slot1_partition: partition@44800 {
 			label = "image-1";
 			reg = <0x00044800 DT_SIZE_K(234)>;
 		};
+
 		/* Set 4Kb of storage at the end of the 512Kb of flash */
 		storage_partition: partition@7f000 {
 			label = "storage";