ath10k: fix WEP Shared authentication

Frames received from FW were treated incorrectly.
This led to stations being unable to associate to
WEP Shared ath10k AP. This was indicated by a
bizarre hostapd message:

  Unsupported authentication algorithm (36088)

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