Add core/fallback encoder behaviour (#20320)

keyboards/pearlboards/zeus/zeus.c

@@ -15,20 +15,3 @@
  */
 
 #include "zeus.h"
-
-// Encoder rotate function
-#ifdef ENCODER_ENABLE
-bool encoder_update_kb(uint8_t index, bool clockwise) {
-    if (!encoder_update_user(index, clockwise)) {
-        return false;
-    }    /* First encoder */
-    if (index == 0) {
-        if (clockwise) {
-            tap_code(KC_AUDIO_VOL_UP);
-        } else {
-            tap_code(KC_AUDIO_VOL_DOWN);
-        }
-    }
-    return true;
-}
-#endif