Add core/fallback encoder behaviour (#20320)

keyboards/tau4/tau4.c

@@ -17,20 +17,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 #include "quantum.h"
 
-#ifdef ENCODER_ENABLE
-bool encoder_update_kb(uint8_t index, bool clockwise) {
-    if (!encoder_update_user(index, clockwise)) { return false; }
-    if (index == 0) { /* First encoder */
-        if (clockwise) {
-            tap_code(KC_VOLU);
-        } else {
-            tap_code(KC_VOLD);
-        }
-    }
-    return true;
-}
-#endif
-
 #ifdef OLED_ENABLE
 bool oled_task_kb(void) {
     if (!oled_task_user()) { return false; }