shdma: add R-Car Audio DMAC peri peri driver

Add support Audio DMAC peri peri driver
for Renesas R-Car Gen2 SoC, using 'shdma-base'
DMA driver framework.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
[fixed checkpatch error]
Signed-off-by: Vinod Koul <vinod.koul@intel.com>