DMA initialization is started with host sending DMA_ALLOC_NOTIFY bus message
(that includes RX buffer) and FW responds with DMA_ALLOC_NOTIFY_ACK.
Additionally to DMA address communication, this sequence checks capabilities:
-if thw host doesn't support DMA, then it won't send DMA allocation, so FW can't
+if the host doesn't support DMA, then it won't send DMA allocation, so FW can't
send DMA; if FW doesn't support DMA then it won't respond with
DMA_ALLOC_NOTIFY_ACK, in which case host will not use DMA transfers.
Here ISH acts as busmaster DMA controller. Hence when host sends DMA_XFER,