mac80211: don't check netdev state for debugfs read/write

commit 923eaf367206e01f22c97aee22300e332d071916 upstream.

Doing so will lead to an oops for a p2p-dev interface, since it has
no netdev.

Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>