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
diff --git a/Android.mk b/Android.mk
index 725436a..2f8c194 100644
--- a/Android.mk
+++ b/Android.mk
@@ -206,6 +206,10 @@
     LOCAL_C_INCLUDES += system/extras/ext4_utils external/openssl/include
 endif
 
+ifeq ($(TARGET_BOARD_PLATFORM),rk30xx)
+LOCAL_CFLAGS += -DRK3066
+endif
+
 include $(BUILD_EXECUTABLE)
 
 include $(CLEAR_VARS)