ath10k: add support for qca6174

The QCA6174 in combination with new wmi-tlv firmware is capable of
multi-channel, beamforming, tdls and other features.

This patch just makes it possible to boot these devices and do some basic stuff
like connect to an AP without encryption. Some things may not work or may be
unreliable. New features will be implemented later. This will be addressed
eventually with future patches.

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