ASoC: dt-bindings: renesas,rsnd.yaml: drop "dmas/dma-names" from "rcar_sound,ssi"

SSI is supporting both "PIO mode" and "DMA mode", thus "dmas/dma-names"
are not mandatory property. Drop these from rcar_sound,ssi's required:.
This is prepare for Gen4 support. See more details on Link

Link: https://lore.kernel.org/all/[email protected]/#r
Link: https://lore.kernel.org/all/[email protected]/#r
Link: https://lore.kernel.org/all/[email protected]/#r
Link: https://lore.kernel.org/all/[email protected]/#r
Signed-off-by: Kuninori Morimoto <[email protected]>
Reviewed-by: Geert Uytterhoeven <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mark Brown <[email protected]>

Author: morimoto

Documentation/devicetree/bindings/sound/renesas,rsnd.yaml

@@ -256,8 +256,6 @@ properties:
             $ref: /schemas/types.yaml#/definitions/flag
         required:
           - interrupts
-          - dmas
-          - dma-names
     additionalProperties: false
 
   # For DAI base