ath10k: add a support of set_tsf on vdev interface

10.2.4.70.24 firmware introduces new feature to set TSF
via vdev parameter, hence implement relevant function.
set_tsf function can be used to shift TBTT that will
help avoid its clockdrift which happens when beacons
are collided.

Signed-off-by: Peter Oh <poh@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>