wifi: mac80211: check S1G action frame size

[ Upstream commit 19e4a47e

 ]

Before checking the action code, check that it even
exists in the frame.

Reported-by:  <syzbot+be9c824e6f269d608288@syzkaller.appspotmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>