mac80211: fix locking in ieee80211_restart_work()

Ilan's change to move locking around accidentally lost the
wiphy_lock() during some porting, add it back.

Fixes: 45daaa13

 ("mac80211: Properly WARN on HW scan before restart")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Link: https://lore.kernel.org/r/20210817121210.47bdb177064f.Ib1ef79440cd27f318c028ddfc0c642406917f512@changeid
Signed-off-by: Jakub Kicinski <kuba@kernel.org>