mac80211: add missing DRIVER_11N_SUPPORT selects

Multiple drivers were missing their DRIVER_11N_SUPPORT despite
supporting 11N capable cards.

Signed-off-by: Jonas Gorski <jogo@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@35711 3c298f89-4303-0410-b956-a3cf2f4a3e73