ath10k: add support for parsing per STA rx_duration for 10.2.4

Add support for parsing 'peer_rx_duration' as part
of 10.2.4 peer_stats. Also register PEER_STATS service
for parsing 'rx_duration' (and for any new fields to be added
as part of peer_stats). Have checks for backward compatibility with
older 10.2.4 firmware incase PEER_STATS service is not enabled

Signed-off-by: Mohammed Shafi Shajakhan <mohammed@qti.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>