ar71xx: image: fix size verification in the CatFiles macro

The macro checks the size of the rootfs image even if
the second parameter of the macro contains the size of
an eraseblock. It is wrong because the size of the
kernel image will be adjusted to the next eraseblock
and the resulting image might be too large.

Fix the macro to check the size of the final image
instead of the rootfs image.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@39383 3c298f89-4303-0410-b956-a3cf2f4a3e73
ar71xx: image: detect partition sizes in the Image/Build/Ath macro

Get the size of the mtd partitions directly from the
MTD layout and remove the superfluous macro parameters.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@39384 3c298f89-4303-0410-b956-a3cf2f4a3e73