ath10k: fix multiple key static wep with ibss

Apparently firmware requires both pairwise and
groupwise keys to be installed per-peer for static
WEP in IBSS. This wasn't necessary for AP mode
(and installing both doesn't seem to break AP
mode thus there's no special handling).

Also there seems to be some kind of issue with
mapping tx/rx keys in firmware properly which
resulted in wrong keys being used and broken
communication between devices.

It can be argued the vdev param part is more of a
workaround than a real fix. However I couldn't
figure out how to fix this differently. It works
and isn't super ugly.

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