Lock sleep when USB is initialized

Added logic to lock deep sleep when USB is initialized to prevent malfunctioning. This is consistent with the other drivers. See PR ARMmbed#9879

Author: AGlass0fMilk

usb/device/targets/TARGET_NORDIC/TARGET_MCU_NRF52840/USBPhy_Nordic.cpp

@@ -70,6 +70,14 @@ USBPhyHw::~USBPhyHw()
 void USBPhyHw::init(USBPhyEvents *events)
 {
 
+    // Disable the USBD interrupts
+    // Interrupts will be reenabled by the Nordic driver
+    NRFX_IRQ_DISABLE(USBD_IRQn);
+
+    if(this->events == NULL) {
+	sleep_manager_lock_deep_sleep();
+    }
+
     this->events = events;
 
     ret_code_t ret;
@@ -125,6 +133,10 @@ void USBPhyHw::deinit()
     // Disable the power peripheral driver
     nrfx_power_uninit();
 
+    if(this->events != NULL) {
+	sleep_manager_unlock_deep_sleep();
+    }
+
     // Clear the instance pointer
     instance = 0;
 }