Added Heltec V4.3 support/FEM autodetection

sx126x.h

@@ -74,6 +74,7 @@ public:
   void disableCrc();
   void enableTCXO();
   void disableTCXO();
+  void setDCDCRegulator();
 
   void rxAntEnable();
   void loraMode();
@@ -97,6 +98,8 @@ public:
 
   void dumpRegisters(Stream& out);
 
+  bool isKCT8103L() { return _kct8103l; }
+
 private:
   void explicitHeaderMode();
   void implicitHeaderMode();
@@ -107,7 +110,8 @@ public:
   // Poll for deferred DIO0 interrupt (call from main loop)
   void pollDio0();
 
-private:  uint8_t readRegister(uint16_t address);
+private:  
+  uint8_t readRegister(uint16_t address);
   void writeRegister(uint16_t address, uint8_t value);
   uint8_t singleTransfer(uint8_t opcode, uint16_t address, uint8_t value);
 
@@ -142,6 +146,7 @@ private:
   int _fifo_rx_addr_ptr;
   uint8_t _packet[255];
   bool _preinit_done;
+  bool _kct8103l;
   volatile bool _dio0_risen;
   void (*_onReceive)(int);
 };