mac80211: wl12xx: build them again

WL_TI is bool but was set to =m, which deactivated it. Now it is set to 
=y and should be activated in the config so the wl12xx driver gets 
build.

This closes #14212.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>


git-svn-id: svn://svn.openwrt.org/openwrt/trunk@38333 3c298f89-4303-0410-b956-a3cf2f4a3e73