[SX126x] Set DIO2 to RF switch by default for FSK too

In commit a1f94d9f ([SX126x] Set DIO2 to RF switch by default), this was
changed for LoRa modulation in begin(), but since this is really
a board-specific attribute, independent of the modulation used, there is
no reason to have a different default for FSK (so this was probably just
forgotten).

src/modules/SX126x/SX126x.cpp

@@ -150,7 +150,7 @@ int16_t SX126x::beginFSK(float br, float freqDev, float rxBw, uint16_t preambleL
   state = setCRC(2);
   RADIOLIB_ASSERT(state);
 
-  state = setDio2AsRfSwitch(false);
+  state = setDio2AsRfSwitch(true);
   RADIOLIB_ASSERT(state);
 
   return(state);