Add missing layer dip switch code for Keychron V2 (vial-kb#447)

* Add missing layer `dip switch` for Keychron V2

* Add missing `#if defined` block in `v2.c`

Author: adophoxia

keyboards/keychron/v2/v2.c

@@ -26,10 +26,21 @@ const matrix_row_t matrix_mask[] = {
 
 #ifdef DIP_SWITCH_ENABLE
 
+bool dip_switch_update_kb(uint8_t index, bool active) {
+    if (!dip_switch_update_user(index, active)) { return false;}
+    if (index == 0) {
+        default_layer_set(1UL << (active ? 1 : 0));
+    }
+    return true;
+}
+
+#endif // DIP_SWITCH_ENABLE
+
+#if defined(RGB_MATRIX_ENABLE) && defined(CAPS_LOCK_LED_INDEX)
+
 bool process_record_kb(uint16_t keycode, keyrecord_t *record) {
     if (!process_record_user(keycode, record)) { return false; }
     switch (keycode) {
-#ifdef RGB_MATRIX_ENABLE
         case RGB_TOG:
             if (record->event.pressed) {
                 switch (rgb_matrix_get_flags()) {
@@ -47,12 +58,13 @@ bool process_record_kb(uint16_t keycode, keyrecord_t *record) {
                 rgb_matrix_enable();
             }
             return false;
-#endif
     }
     return true;
 }
 
 void rgb_matrix_indicators_advanced_kb(uint8_t led_min, uint8_t led_max) {
+    // RGB_MATRIX_INDICATOR_SET_COLOR(index, red, green, blue);
+
     if (host_keyboard_led_state().caps_lock) {
         RGB_MATRIX_INDICATOR_SET_COLOR(CAPS_LOCK_LED_INDEX, 255, 255, 255);
     } else {