Work around MEMERASE ioctl for rk3066 compatibility

Due to a kernel bug and no available sources we have to work around the
MEMERASE ioctl - if used, it hangs and never returns. I straced the original
recovery executable and could see that it is simply calling write() with a
bunch of zeroes instead of using MEMERASE.

Added a hack that does the same and now the resulting TWRP recovery image works.

Change-Id: I1b1c1c9e870e350776346bdca5d442c7ef565aa0

mtdutils/Android.mk

@@ -7,9 +7,14 @@ LOCAL_SRC_FILES := \
 	mtdutils.c \
 	mounts.c 
 
+ifeq ($(TARGET_BOARD_PLATFORM),rk30xx)
+LOCAL_SRC_FILES += rk30hack.c
+endif
+
 LOCAL_MODULE := libmtdutils
 LOCAL_STATIC_LIBRARIES := libcutils libc
 LOCAL_FORCE_STATIC_EXECUTABLE := true
+
 include $(BUILD_STATIC_LIBRARY)
 
 endif	# !TARGET_SIMULATOR