cfg80211: fix regulatory NULL dereference

cfg80211: fix regulatory NULL dereference

commit de3584bd62d87b4c250129fbc46ca52c80330add upstream.

By the time userspace returns with a response to
the regulatory domain request, the wiphy causing
the request might have gone away. If this is so,
reject the update but mark the request as having
been processed anyway.

Cc: Luis R. Rodriguez <lrodriguez@qca.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>