Bluetooth GATT callback naming fix "Ext" -> "" (1/2)

Gatt callback don't need the "Ext" postfix, as it was removed from new
API.

Test: manual
Bug: 30622771
Change-Id: I54596ffdcb818343cc313123266cfa16291c6236
diff --git a/core/java/android/bluetooth/BluetoothGatt.java b/core/java/android/bluetooth/BluetoothGatt.java
index a314aaf..99ca11e 100644
--- a/core/java/android/bluetooth/BluetoothGatt.java
+++ b/core/java/android/bluetooth/BluetoothGatt.java
@@ -135,8 +135,8 @@
     /**
      * Bluetooth GATT callbacks. Overrides the default BluetoothGattCallback implementation.
      */
-    private final IBluetoothGattCallbackExt mBluetoothGattCallback =
-        new IBluetoothGattCallbackExt.Stub() {
+    private final IBluetoothGattCallback mBluetoothGattCallback =
+        new IBluetoothGattCallback.Stub() {
             /**
              * Application interface registered - app is ready to go
              * @hide