Android: Add input device selection

Source/Android/jni/Input/EmulatedController.h

@@ -0,0 +1,13 @@
+// Copyright 2022 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <jni.h>
+
+namespace ControllerEmu
+{
+class ControlReference;
+}
+
+ControllerEmu::EmulatedController* EmulatedControllerFromJava(JNIEnv* env, jobject obj);