Patch from Catalin Marinas

This patch calculates the AFS partition length by expanding the image
length information to the nearest erase block boundary. This
eliminates the problems with JFFS2 erasing the footer.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>