mac80211: copy nl80211 mgmt TX SKB for status

When we return the TX status for an nl80211 mgmt TX SKB, we
should also return the original frame with the status to
allow userspace to match up the submission (it could also
use the cookie but both ways are permissible.)

As TX SKBs could be encrypted, at least in the case of ANQP
while associated with the AP, copy the original SKB, store
it with an ACK frame ID and restructure the status path to
use that to return status with the original SKB. Otherwise,
userspace (in particular wpa_supplicant) will get confused.

Reported-by: Matti Gottlieb <matti.gottlieb@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>