mac80211: fix rt2x00 dependency

The current dependency prevents building of the
rt2800{pci,usb} drivers for RT3883. Change the
dependency to fix this.

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

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@37699 3c298f89-4303-0410-b956-a3cf2f4a3e73