mac80211: add ieee80211_tx_status_ext

This allows the driver to pass in struct ieee80211_tx_status directly.
Make ieee80211_tx_status_noskb a wrapper around it.

As with ieee80211_tx_status_noskb, there is no _ni variant of this call,
because it probably won't be needed.

Even if the driver won't provide any extra status info other than what's
in struct ieee80211_tx_info already, it can optimize status reporting
this way by passing in the station pointer.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
[use C99 initializers]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>