AP mode currently sets up the dual stream capability
for all stations. This patch fixes it by checking if the
associated station supports dual stream MCS rates (8-15).
We would disregard any MCS rates above 15, since Atheros
HW supports only 0..15 rates currently, and can't receive
at rates > 15 anyway.
Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>