rb532: switch to 3.6.11

Compile tested only. The target is broken anyway,
so the kernel version does not matter too much.

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

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@34809 3c298f89-4303-0410-b956-a3cf2f4a3e73