LinuxKPI: 802.11: implement wiphy_{,un}lock()

This will help us to get minimally better lock coverage in iwlwifi
though not yet against the LinuxKPI implementation which will likely
switch to this in the future. At least the TODO() logging noise is
out of the way.

Sponsored by: The FreeBSD Foundation

(cherry picked from commit 95a7aa8009877ca95d81967f9af568ef832bb565)