Remove NRF52BoardOTA class and integrate it into NRF52Board

As all NRF52 boards now have OTA support, let's remove the subclass
and integrate it into the base class.

Signed-off-by: Frieder Schrempf <frieder@fris.de>

variants/sensecap_solar/SenseCapSolarBoard.h

@@ -4,9 +4,9 @@
 #include <Arduino.h>
 #include <helpers/NRF52Board.h>
 
-class SenseCapSolarBoard : public NRF52BoardDCDC, public NRF52BoardOTA {
+class SenseCapSolarBoard : public NRF52BoardDCDC {
 public:
-  SenseCapSolarBoard() : NRF52BoardOTA("SENSECAP_SOLAR_OTA") {}
+  SenseCapSolarBoard() : NRF52Board("SENSECAP_SOLAR_OTA") {}
   void begin();
 
 #if defined(P_LORA_TX_LED)