wl12xx: allow 11a AP-mode for wl127x devices

There was a check preventing 127x devices from using the 11a band when
operating as AP. Since we now support this functionality, remove the
check.

With this patch, a 11a AP starts ok on 127x cards.

Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>