Drop Adnroid.mk and Application.mk in samples as they are not used with Gradle.

samples/android/tutorial-2-mixedprocessing/jni/Android.mk

@@ -1,19 +0,0 @@
-LOCAL_PATH := $(call my-dir)
-
-include $(CLEAR_VARS)
-
-ifdef OPENCV_ANDROID_SDK
-  ifneq ("","$(wildcard $(OPENCV_ANDROID_SDK)/OpenCV.mk)")
-    include ${OPENCV_ANDROID_SDK}/OpenCV.mk
-  else
-    include ${OPENCV_ANDROID_SDK}/sdk/native/jni/OpenCV.mk
-  endif
-else
-  include ../../sdk/native/jni/OpenCV.mk
-endif
-
-LOCAL_MODULE    := mixed_sample
-LOCAL_SRC_FILES := jni_part.cpp
-LOCAL_LDLIBS +=  -llog -ldl
-
-include $(BUILD_SHARED_LIBRARY)

samples/android/tutorial-2-mixedprocessing/jni/Application.mk

@@ -1,4 +0,0 @@
-APP_STL := gnustl_static
-APP_CPPFLAGS := -frtti -fexceptions
-APP_ABI := armeabi-v7a
-APP_PLATFORM := android-8