ath10k: fix multi BSSID with WPA on FW 10.1

FW 10.1 seems to require the default key index to
be updated to point to group key after it is
installed. Otherwise Txed frames are corrupted.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
(cherry picked from commit cfb27d29b61cc32c0bb75f741aeabb9c6e6af742)