ath10k: add FW API support to test mode

Add WMI-TLV and FW API support in ath10k testmode.
Ath10k can get right wmi command format from UTF image
to communicate UTF firmware.

Signed-off-by: Alan Liu <alanliu@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>