add support for user button on rak wismesh pocket which uses RAK4630 internally

Boards.h

@@ -569,6 +569,7 @@
       #define HAS_TCXO true
       #define HAS_RF_SWITCH_RX_TX true
       #define HAS_BUSY true
+      #define HAS_INPUT true
       #define DIO2_AS_RF_SWITCH true
       #define CONFIG_UART_BUFFER_SIZE 6144
       #define CONFIG_QUEUE_SIZE 6144
@@ -578,6 +579,8 @@
       #define BLE_MANUFACTURER "RAK Wireless"
       #define BLE_MODEL "RAK4640"
 
+      const int pin_btn_usr1 = 9;
+
       // Following pins are for the sx1262
       const int pin_rxen = 37;
       const int pin_reset = 38;

RNode_Firmware.ino

@@ -1389,7 +1389,7 @@ void sleep_now() {
 }
 
 void button_event(uint8_t event, unsigned long duration) {
-  #if MCU_VARIANT == MCU_ESP32
+  #if MCU_VARIANT == MCU_ESP32 || MCU_VARIANT == MCU_NRF52
     if (display_blanked) {
       display_unblank();
     } else {