Watchdog cleanup (#15283)

Marlin/src/HAL/HAL_LINUX/HAL.h

@@ -97,6 +97,10 @@ void HAL_adc_enable_channel(int pin);
 void HAL_adc_start_conversion(const uint8_t adc_pin);
 uint16_t HAL_adc_get_result();
 
+// Reset source
+inline void HAL_clear_reset_source(void) {}
+inline uint8_t HAL_get_reset_source(void) { return RST_POWER_ON; }
+
 /* ---------------- Delay in cycles */
 FORCE_INLINE static void DELAY_CYCLES(uint64_t x) {
   Clock::delayCycles(x);