ath10k: add support for HTT 3.0

New firmware comes with new HTT protocol version.
In 3.0 the separate mgmt tx command has been
removed. All traffic is to be pushed through data
tx (tx_frm) command with a twist - FW seems to not
be able (yet?) to access tx fragment table so for
manamgement frames frame pointer is passed
directly.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>