wil6210: fix wiphy registration sequence

Currently wiphy structure is initialized and registered
in wil_if_alloc, before some information is available such
as MAC address and capabilities. As a result there is a
small chance user space will get incorrect information
from calls such as NL80211_CMD_GET_WIPHY.
Fix this by seperating the registration and moving it
to wil_if_add which is executed later, after all
relevant information is known.

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>