dmaengine: imx-sdma: Add device to device support

This patch adds DEV_TO_DEV support for i.MX SDMA driver to support data
transfer between two peripheral FIFOs.
The per_2_per script requires two peripheral addresses and two DMA
requests, and it need to check the src addr and dst addr is in the SPBA
bus space or in the AIPS bus space.

Signed-off-by: Shengjiu Wang <shengjiu.wang@freescale.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>