arm64: dts: actions: Add DMA Controller for S700

This commit adds DMA controller present on Actions S700, it differs from
S900 in terms of number of dma channels and requests.

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Amit Singh Tomar <amittomer25@gmail.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>