arm64: dts: Add APM X-Gene SoC DMA device and DMA clock DTS nodes

This patch adds the device tree node for APM X-Gene SoC
DMA controller and DMA clock.

Signed-off-by: Rameshwar Prasad Sahu <rsahu@apm.com>
Signed-off-by: Loc Ho <lho@apm.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>