ath10k: implement WMI events handling frame for both firmwares

We still use the same function handlers for both main and 10.X
paths. Next step is to track down and make the split needed.

Signed-off-by: Bartosz Markowski <bartosz.markowski@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>