soc: RT685: Add USB support

1. Update soc.c file to add USB clock setup
2. Add a linker script file to move USB transfer
   buffer and controller buffers to USB RAM
3. Update Kconfig's to add USB support
4. Add zephyr_udc0 nodelabel

Signed-off-by: Mahesh Mahadevan <mahesh.mahadevan@nxp.com>

boards/arm/mimxrt685_evk/doc/index.rst

@@ -93,6 +93,8 @@ features:
 +-----------+------------+-------------------------------------+
 | SDHC      | on-chip    | disk access                         |
 +-----------+------------+-------------------------------------+
+| USB       | on-chip    | USB device                          |
++-----------+------------+-------------------------------------+
 
 The default configuration can be found in the defconfig file:
 

boards/arm/mimxrt685_evk/mimxrt685_evk_cm33.dts

@@ -302,3 +302,7 @@ i2s1: &flexcomm3 {
 	status = "okay";
 	pwr-gpios = <&gpio2 10 GPIO_ACTIVE_HIGH>;
 };
+
+zephyr_udc0: &usbhs {
+	status = "okay";
+};

boards/arm/mimxrt685_evk/mimxrt685_evk_cm33.yaml

@@ -28,3 +28,4 @@ supported:
   - sdhc
   - spi
   - watchdog
+  - usb_device