ath10k: fix broken traffic for static WEP in IBSS

When WEP keys are uploaded it's possible that
there are stations associated already (e.g. when
merging) without any keys. Static WEP needs an
explicit per-peer key upload.

Make sure to re-upload wep keys if necessary.

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