Fix jsonschema, fix missing mcu_reset

Author: Jpe230

data/schemas/keyboard.jsonschema

@@ -105,7 +105,7 @@
                 "unknown",
                 "usbasploader",
                 "wb32-dfu",
-                "sn32_dfu"
+                "sn32-dfu"
             ]
         },
         "bootloader_instructions": {

platforms/chibios/bootloaders/sn32_dfu.c

@@ -46,3 +46,7 @@ void enter_bootloader_mode_if_requested(void) {
             ;
     }
 }
+
+__attribute__((weak)) void mcu_reset(void) {
+    NVIC_SystemReset();
+}