greybus: build: remove Android makefile

There is no standard way of building a kernel from source in
Android.  Each device/SoC can (and do) implement it in their own way.
To that end, let's remove this makefile and let each device define
how they want to build the modules.
Signed-off-by: Michael Scott <michael.scott@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/Android.mk

-.PHONY: build-greybus
-
-ifneq ($(TARGET_NO_KERNEL), true)
-$(PRODUCT_OUT)/ramdisk.img: build-greybus
-endif
-
-GREYBUS_MODULE_OUT_PATH := $(PRODUCT_OUT)/root/lib/modules
-GREYBUS_CC_PREFIX := $(shell cd `dirname $(TARGET_TOOLS_PREFIX)` && pwd)/$(shell basename $(TARGET_TOOLS_PREFIX))
-
-include $(CLEAR_VARS)
-GREYBUS_SRC_PATH := $(ANDROID_BUILD_TOP)/external/greybus/
-LOCAL_PATH := $(GREYBUS_SRC_PATH)
-LOCAL_SRC_FILES := greybus.ko
-LOCAL_MODULE := $(LOCAL_SRC_FILES)
-LOCAL_MODULE_CLASS := EXECUTABLES
-LOCAL_MODULE_PATH := $(GREYBUS_MODULE_OUT_PATH)
-$(LOCAL_PATH)/$(LOCAL_SRC_FILES): build-greybus
-include $(BUILD_PREBUILT)
-
-KDIRARG := KERNELDIR="${ANDROID_PRODUCT_OUT}/obj/kernel"
-ARCHARG := ARCH=$(TARGET_ARCH)
-FLAGARG := EXTRA_CFLAGS+=-fno-pic
-ARGS := $(KDIRARG) $(ARCHARG) $(FLAGARG)
-
-build-greybus: $(INSTALLED_KERNEL_TARGET)
-	make clean -C $(GREYBUS_SRC_PATH)
-	cd $(GREYBUS_SRC_PATH) &&\
-	$(MAKE) -j$(MAKE_JOBS) CROSS_COMPILE=$(GREYBUS_CC_PREFIX) $(ARGS)
-	mkdir -p $(GREYBUS_MODULE_OUT_PATH)
-	ko=`find $(GREYBUS_SRC_PATH) -type f -name "*.ko"`;\
-	for i in $$ko; do $(GREYBUS_CC_PREFIX)strip --strip-unneeded $$i;\
-	mv $$i $(GREYBUS_MODULE_OUT_PATH)/; done;