MAGIC value for powerReason should be stored in RTC backup on Horus (#7096)

- Allows the radio main application to start correctly when coming from an app in RAM
- Refactoring of the `UNEXPECTED_SHUTDOWN()` process
- Saves the RTC battery as BACKUP RAM is not needed on normal shutdown
- On PWR OFF on an ALERT, the radio won't show the next alert before shutting down
- Bootloader flashable through the SD Manager

radio/src/targets/sky9x/lcd_driver.cpp

@@ -120,7 +120,7 @@ void lcdInit()
       TC0->TC_CHANNEL[0].TC_CCR = 5; // Enable clock and trigger it (may only need trigger)
       while ( TC0->TC_CHANNEL[0].TC_CV < 36000 ) {
         // Value depends on MCK/2 (used 18MHz) give 2mS delay
-        wdt_reset(); // Wait
+        WDG_RESET(); // Wait
       }
     }
   }