cfg80211: prepare for const netdev->dev_addr

netdev->dev_addr will be const soon.
All callers of wdev_address() can take const already.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20211019162816.1384077-2-kuba@kernel.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -5558,7 +5558,7 @@ struct wireless_dev {
 	unsigned long unprot_beacon_reported;
 };
 
-static inline u8 *wdev_address(struct wireless_dev *wdev)
+static inline const u8 *wdev_address(struct wireless_dev *wdev)
 {
 	if (wdev->netdev)
 		return wdev->netdev->dev_addr;