realview: switch to 3.8

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

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@35939 3c298f89-4303-0410-b956-a3cf2f4a3e73
realview: remove 3.3 support

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

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@35940 3c298f89-4303-0410-b956-a3cf2f4a3e73