ramipe: disable HG255D support

Signed-off-by: John Crispin <blogic@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@37531 3c298f89-4303-0410-b956-a3cf2f4a3e73
ramips: disable hg255d

Signed-off-by: John Crispin <blogic@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@37532 3c298f89-4303-0410-b956-a3cf2f4a3e73