Add via support for 6key (#18082)

keyboards/handwired/6key/keymaps/default/keymap.c

@@ -15,33 +15,18 @@
   */
 #include QMK_KEYBOARD_H
 
-#define _MAIN 0
-#define _FN 1
-
-#define KC_UNDO LCTL(KC_Z)
-#define KC_REDO LCTL(KC_Y)
+enum layers{
+  _MAIN,
+  _FN
+};
 
 const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
   [_MAIN] = LAYOUT(
-    KC_UNDO,  KC_REDO,  KC_A,
-    KC_C,     KC_D,     KC_S
+    KC_Z, KC_Y, KC_A,
+    KC_C, KC_D, KC_S
   ),
-
   [_FN] = LAYOUT(
     KC_F13, KC_F14, KC_F15,
     KC_F16, KC_F17, KC_F18
   )
 };
-
-bool dip_switch_update_user(uint8_t index, bool active) {
-    switch (index) {
-        case 0: {
-            if (active) {
-                set_single_persistent_default_layer(_FN);
-            } else {
-                set_single_persistent_default_layer(_MAIN);
-            }
-        }
-    }
-    return true;
-}