ramips: add support for A5-V11 board (resubmit)

(Reposted due to an issue with the patchwork server during original submission)

Unbranded. Silkscreen on PCB is “A5-V11”, believed to be made by Bococom (or at least uses Bococom image encryption - as used on poray devices - but different key)

Signed-off-by: Gareth Bryan <gareth@mx9.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@43102 3c298f89-4303-0410-b956-a3cf2f4a3e73