ath6kl: Configure htcap in fw based on the channel type in AP mode

This patch disables HT in start_ap if the type of the channel on
which the AP mode is going to be operating is non-HT. HT is enabled
with default ht cap setting if the operating channel is going to be
11n.

Signed-off-by: Vasanthakumar Thiagarajan <vthiagar@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>