mac80211: add KCOV remote annotations to incoming frame processing

Add KCOV remote annotations to ieee80211_iface_work() and
ieee80211_rx_list(). This will enable coverage-guided fuzzing of
mac80211 code that processes incoming 802.11 frames.

Signed-off-by: Aleksandr Nogikh <nogikh@google.com>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>