wil6210: extract firmware capabilities from FW file

When driver is loaded, extract a capabilities record
from the FW file. This record contains bits indicating
which optional features are supported by this FW.
The driver can use this information to determine
which functionality to support and/or expose to user
space.
The extraction is done before wiphy structure is
registered, because the capabilities can affect
information published by the this structure.

Signed-off-by: Lior David <qca_liord@qca.qualcomm.com>
Signed-off-by: Maya Erez <qca_merez@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>