Marlin: Use strcmp_P

Marlin/src/gcode/queue.cpp

@@ -523,12 +523,12 @@ void GCodeQueue::get_serial_commands() {
 
         #if DISABLED(EMERGENCY_PARSER)
           // Process critical commands early
-          if (strcmp(command, "M108") == 0) {
+          if (strcmp_P(command, PSTR("M108")) == 0) {
             wait_for_heatup = false;
             TERN_(HAS_LCD_MENU, wait_for_user = false);
           }
-          if (strcmp(command, "M112") == 0) kill(M112_KILL_STR, nullptr, true);
+          if (strcmp_P(command, PSTR("M112")) == 0) kill(M112_KILL_STR, nullptr, true);
-          if (strcmp(command, "M410") == 0) quickstop_stepper();
+          if (strcmp_P(command, PSTR("M410")) == 0) quickstop_stepper();
         #endif
 
         #if defined(NO_TIMEOUTS) && NO_TIMEOUTS > 0