ath10k: fix aid setup in station mode

While debugging something else I noticed AID was
set to 0. This could lead to powersave issues in
station mode. Maybe this isn't really necessary
but set it properly just to be sure.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>