2.4 continued (#8092)

Quite a bit of work on 2.4

Co-authored-by: 3djc <Th1sisfmyofmyo>

radio/src/targets/simu/simpgmspace.cpp

@@ -734,6 +734,11 @@ uint16_t getBatteryVoltage()
   return (g_eeGeneral.vBatWarn * 10) + 50; // 0.5 volt above alerm (value is PREC1)
 }
 
+uint16_t getRTCBatteryVoltage()
+{
+  return 300;
+}
+
 void boardOff()
 {
 }