Use SYS_INIT for BLE and USB init.

app/Kconfig

@@ -15,12 +15,20 @@ config ZMK_KSCAN_EVENT_QUEUE_SIZE
 
 menu "HID Output Types"
 
-config ZMK_USB
+menuconfig ZMK_USB
 	bool "USB"
 	select USB
 	select USB_DEVICE_STACK
 	select USB_DEVICE_HID
 
+if ZMK_USB
+
+config ZMK_USB_INIT_PRIORITY
+	int "Init Priority"
+	default 50
+
+endif
+
 menuconfig ZMK_BLE
 	bool "BLE (HID over GATT)"
 	select BT
@@ -32,6 +40,10 @@ menuconfig ZMK_BLE
 
 if ZMK_BLE
 
+config ZMK_BLE_INIT_PRIORITY
+	int "Init Priority"
+	default 50
+
 # HID GATT notifications sent this way are *not* picked up by Linux, and possibly others.
 config BT_GATT_NOTIFY_MULTIPLE
 	default n