This image is supposed to be written with help of bootloader to the
flash, but as it stands, it's not aligned to block size and RedBoot will
happily create non-aligned partition size in FIS directory. This could
lead to kernel to mark the partition as read-only, therefore pad the
image to block erase size boundary.
Signed-off-by: Tomasz Maciej Nowak <tmn505@gmail.com>