apps: aboot: Add check to prevent buffer overread in cmd_flash_mmc_img

Add check to confirm the size of given image is greater than BOOT_MAGIC_SIZE
which unchecked may cause OOB error while flashing boot/recovery images on
emmc targets.

Change-Id: I6e8c104641262e2d0c443294bb82af360c298972
Signed-off-by: Ashish Bhimanpalliwar <abhiman@codeaurora.org>
1 file changed