dma: imx-sdma: Add sdma firmware version 2 support

On i.MX5/6 series, SDMA is using new version firmware to support SSI
dual FIFO feature and HDMI Audio (i.MX6Q/DL only). Thus add it.

Signed-off-by: Nicolin Chen <b42378@freescale.com>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>