ath10k: implement host memory chunks

10.X firmware can request a memory pool from host to offload
it's own resources. This is a feature designed especially
for AP mode where the target has to deal with large number
of peers.

So we allocate and map a consistent DMA memory which FW can
use to store e.g. peer rate contol maps.

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