Add M997 support and simple implementation for LPC176x (#13281)

Marlin/src/gcode/control/M997.cpp

@@ -0,0 +1,34 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (C) 2019 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (C) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "../gcode.h"
+
+#if ENABLED(PLATFORM_M997_SUPPORT)
+
+/**
+ * M997: Perform in-application firmware update
+ */
+void GcodeSuite::M997() {
+  flashFirmware(parser.intval('S'));
+}
+
+#endif