wl12xx: AP-mode - configure HT rate support to the FW

Unconditionally configure HT rate support to the FW on all ACs
when starting the AP.

When 11n support is disabled by usermode (hostapd), each STA joining
the AP will appear as a non-HT STA. This will stop us from accidentally
transmitting using MCS rates.

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