dma: imx-sdma: Add new dma type for ssi dual fifo script

This patch adds a new DMA_TYPE for SSI dual FIFO script, included
in SDMA firmware version 2. This script would allow SSI use dual
fifo mode to transimit/receive data without occasional hardware
underrun/overrun.

Signed-off-by: Nicolin Chen <[e-mail]>
Acked-by: Kumar Gala <[e-mail]>
Acked-by: Sascha Hauer <[e-mail]>
Signed-off-by: Vinod Koul <[e-mail]>

Documentation/devicetree/bindings/dma/fsl-imx-sdma.txt

···
 	19	IPU Memory
 	20	ASRC
 	21	ESAI
+	22	SSI Dual FIFO	(needs firmware ver >= 2)
 
 The third cell specifies the transfer priority as below.
 

drivers/dma/imx-sdma.c

···
 		per_2_emi = sdma->script_addrs->app_2_mcu_addr;
 		emi_2_per = sdma->script_addrs->mcu_2_app_addr;
 		break;
+	case IMX_DMATYPE_SSI_DUAL:
+		per_2_emi = sdma->script_addrs->ssish_2_mcu_addr;
+		emi_2_per = sdma->script_addrs->mcu_2_ssish_addr;
+		break;
 	case IMX_DMATYPE_SSI_SP:
 	case IMX_DMATYPE_MMC:
 	case IMX_DMATYPE_SDHC:

include/linux/platform_data/dma-imx.h

···
 	IMX_DMATYPE_IPU_MEMORY,	/* IPU Memory */
 	IMX_DMATYPE_ASRC,	/* ASRC */
 	IMX_DMATYPE_ESAI,	/* ESAI */
+	IMX_DMATYPE_SSI_DUAL,	/* SSI Dual FIFO */
 };
 
 enum imx_dma_prio {