Current firmware should work for station mode as well, and the older
firmware will usually behave worse and become unsupported over time.
Also, the MAC address handling on ar71xx is only implemented on one
firmware version.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@46197 3c298f89-4303-0410-b956-a3cf2f4a3e73