Soft Reset via Serial or post-kill button click (#21652)

Co-authored-by: Scott Lahteine <thinkyhead@users.noreply.github.com>

Marlin/src/HAL/TEENSY40_41/HAL.cpp

@@ -120,6 +120,8 @@ uint8_t HAL_get_reset_source() {
   return 0;
 }
 
+void HAL_reboot() { _reboot_Teensyduino_(); }
+
 #define __bss_end _ebss
 
 extern "C" {

Marlin/src/HAL/TEENSY40_41/HAL.h

@@ -121,6 +121,8 @@ void HAL_clear_reset_source();
 // Reset reason
 uint8_t HAL_get_reset_source();
 
+void HAL_reboot();
+
 FORCE_INLINE void _delay_ms(const int delay_ms) { delay(delay_ms); }
 
 #if GCC_VERSION <= 50000