cfg80211: fix memory leak of wiphy device name

In wiphy_new_nm(), if an error occurs after dev_set_name() and
device_initialize() have already been called, it's necessary to call
put_device() (via wiphy_free()) to avoid a memory leak.

Reported-by:  <syzbot+7fddca22578bc67c3fe4@syzkaller.appspotmail.com>
Fixes: 1f87f7d3

 ("cfg80211: add rfkill support")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>