Currently in 10.4 FW, all the received 4addr frames are processed for
source port learning which is enabled by default. This learning can't be
disabled by default in FW since it breaks backward compatibility.

Since ath10k uses mac80211 based 4addr mode, source port learning done in
10.4 FW is redundant and also causes issues when 3addr frames are
transmitted/received for a 4addr station.

One such visible functional impact is when GTK rekey frame from
hostapd based AP to 4addr STA is dropped in AP's 10.4 FW. This is since
GTK rekey EAPOL frame is 3addr frame on AP interface and STA enabled
with 4addr is already allowed for receiving 3addr EAPOL frames.

Source port learning implementation in 10.4 FW drops this 3addr GTK rekey
frame in AP destinated for 4addr STA causing disassociation and
re-association for every GTK rekey session. GTK rekey issue is not seen
when learning is disabled in FW.

To prevent such issues without breaking backward compatibility, FW
advertises new service bit making the source port learning configurable and
this learning is being currently disabled during ath10k vdev creation.

* Tested HW: QCA9984
* Tested FW: 10.4-3.6.0.1-00004
Signed-off-by: Sathishkumar Muruganandam <murugana@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>