ASoC: dt-bindings: renesas,rz-ssi: Update slave dma channel configuration parameter

The DMAC on RZ/G2L has specific slave channel configuration
parameters for SSI.
This patch updates the dmas description and example node to include
the encoded slave channel configuration.
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20210813091156.10700-3-biju.das.jz@bp.renesas.comSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/renesas,rz-ssi.yaml

@@ -48,6 +48,24 @@ properties:
   dmas:
     minItems: 1
     maxItems: 2
+    description:
+      The first cell represents a phandle to dmac
+      The second cell specifies the encoded MID/RID values of the SSI port
+      connected to the DMA client and the slave channel configuration
+      parameters.
+      bits[0:9]   - Specifies MID/RID value of a SSI channel as below
+                    MID/RID value of SSI rx0 = 0x256
+                    MID/RID value of SSI tx0 = 0x255
+                    MID/RID value of SSI rx1 = 0x25a
+                    MID/RID value of SSI tx1 = 0x259
+                    MID/RID value of SSI rt2 = 0x25f
+                    MID/RID value of SSI rx3 = 0x262
+                    MID/RID value of SSI tx3 = 0x261
+      bit[10]     - HIEN = 1, Detects a request in response to the rising edge
+                    of the signal
+      bit[11]     - LVL = 0, Detects based on the edge
+      bits[12:14] - AM = 2, Bus cycle mode
+      bit[15]     - TM = 0, Single transfer mode
 
   dma-names:
     oneOf:
@@ -93,8 +111,8 @@ examples:
             clock-names = "ssi", "ssi_sfr", "audio_clk1", "audio_clk2";
             power-domains = <&cpg>;
             resets = <&cpg R9A07G044_SSI0_RST_M2_REG>;
-            dmas = <&dmac 0x255>,
-                   <&dmac 0x256>;
+            dmas = <&dmac 0x2655>,
+                   <&dmac 0x2656>;
             dma-names = "tx", "rx";
             #sound-dai-cells = <0>;
     };