mpc85xx: add support for linux 3.7

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

git-svn-id: svn://svn.openwrt.org/openwrt@35451 3c298f89-4303-0410-b956-a3cf2f4a3e73
mpc85xx: switch to 3.7

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

git-svn-id: svn://svn.openwrt.org/openwrt@35452 3c298f89-4303-0410-b956-a3cf2f4a3e73
mpc85xx: nuke 3.6 support

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

git-svn-id: svn://svn.openwrt.org/openwrt@35453 3c298f89-4303-0410-b956-a3cf2f4a3e73