dmaengine: hisilicon: Add Kunpeng DMA engine support

This patch adds a driver for HiSilicon Kunpeng DMA engine. This DMA engine
which is an PCIe iEP offers 30 channels, each channel has a send queue, a
complete queue and an interrupt to help to do tasks. This DMA engine can do
memory copy between memory blocks or between memory and device buffer.

Signed-off-by: Zhou Wang <wangzhou1@hisilicon.com>
Signed-off-by: Zhenfa Qiu <qiuzhenfa@hisilicon.com>
Link: https://lore.kernel.org/r/1579155057-80523-1-git-send-email-wangzhou1@hisilicon.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>