recovery: Allow devices to reboot to download mode

Change-Id: I70149ff952aeee83f029db7f634ed5bf95cb54fb

Author: andi34

Android.mk

@@ -124,6 +124,10 @@ endif
     LOCAL_STATIC_LIBRARIES += libext4_utils_static libz
 #endif
 
+ifeq ($(BOARD_HAS_DOWNLOAD_MODE), true)
+    LOCAL_CFLAGS += -DDOWNLOAD_MODE
+endif
+
 LOCAL_CFLAGS += -DUSE_EXT4 -DMINIVOLD
 LOCAL_C_INCLUDES += system/extras/ext4_utils system/core/fs_mgr/include external/fsck_msdos
 LOCAL_C_INCLUDES += system/vold external/e2fsprogs/lib