Allwinner V3s has a DMA engine similar to the ones from A31, but with
fewer channels and DRQs.

Add support for it.
Signed-off-by: NIcenowy Zheng <icenowy@aosc.xyz>
Acked-by: NChen-Yu Tsai <wens@csie.org>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NVinod Koul <vinod.koul@intel.com>