elput: Add case for wheel tilt when getting pointer axis value

libinput >= 1.7.0 added support for
LIBINPUT_POINTER_AXIS_SOURCE_WHEEL_TILT, however we do not yet support
that in elput, thus gcc was spilling a warning about an unhandled
enumeration value here. We'll add a case for the above, plus a default
to cover any future additions.

Signed-off-by: Chris Michael <cp.michael@samsung.com>

src/lib/elput/elput_evdev.c

@@ -908,6 +908,9 @@ _pointer_axis_value(struct libinput_event_pointer *event, enum libinput_pointer_
       case LIBINPUT_POINTER_AXIS_SOURCE_CONTINUOUS:
         val = libinput_event_pointer_get_axis_value(event, axis);
         break;
+      case LIBINPUT_POINTER_AXIS_SOURCE_WHEEL_TILT:
+      default:
+        break;
      }
 
    return val;