Only update the battery level if we're on Bluetooth

Fixes battery level dropping to empty with the Qanba Drone Arcade Stick.

It looks like we might also be able to skip the check for all third party controllers, but I think this is the right thing to do for Sony controllers as well.

src/joystick/hidapi/SDL_hidapi_ps4.c

@@ -919,19 +919,21 @@ HIDAPI_DriverPS4_HandleStatePacket(SDL_Joystick *joystick, SDL_hid_device *dev,
     axis = ((int)packet->ucRightJoystickY * 257) - 32768;
     SDL_PrivateJoystickAxis(joystick, SDL_CONTROLLER_AXIS_RIGHTY, axis);
 
-    if (packet->ucBatteryLevel & 0x10) {
-        SDL_PrivateJoystickBatteryLevel(joystick, SDL_JOYSTICK_POWER_WIRED);
-    } else {
-        /* Battery level ranges from 0 to 10 */
-        int level = (packet->ucBatteryLevel & 0xF);
-        if (level == 0) {
-            SDL_PrivateJoystickBatteryLevel(joystick, SDL_JOYSTICK_POWER_EMPTY);
-        } else if (level <= 2) {
-            SDL_PrivateJoystickBatteryLevel(joystick, SDL_JOYSTICK_POWER_LOW);
-        } else if (level <= 7) {
-            SDL_PrivateJoystickBatteryLevel(joystick, SDL_JOYSTICK_POWER_MEDIUM);
+    if (ctx->device->is_bluetooth) {
+        if (packet->ucBatteryLevel & 0x10) {
+            SDL_PrivateJoystickBatteryLevel(joystick, SDL_JOYSTICK_POWER_WIRED);
         } else {
-            SDL_PrivateJoystickBatteryLevel(joystick, SDL_JOYSTICK_POWER_FULL);
+            /* Battery level ranges from 0 to 10 */
+            int level = (packet->ucBatteryLevel & 0xF);
+            if (level == 0) {
+                SDL_PrivateJoystickBatteryLevel(joystick, SDL_JOYSTICK_POWER_EMPTY);
+            } else if (level <= 2) {
+                SDL_PrivateJoystickBatteryLevel(joystick, SDL_JOYSTICK_POWER_LOW);
+            } else if (level <= 7) {
+                SDL_PrivateJoystickBatteryLevel(joystick, SDL_JOYSTICK_POWER_MEDIUM);
+            } else {
+                SDL_PrivateJoystickBatteryLevel(joystick, SDL_JOYSTICK_POWER_FULL);
+            }
         }
     }