ASoC: rsnd: Add device tree support for r8a77995

Simply document new compat strings.
There appears to be no need for a driver updates.
Signed-off-by: Hiroyuki Yokoyama <hiroyuki.yokoyama.vx@renesas.com>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

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

@@ -277,6 +277,7 @@ Required properties:
 				    - "renesas,rcar_sound-r8a7796" (R-Car M3-W)
 				    - "renesas,rcar_sound-r8a77965" (R-Car M3-N)
 				    - "renesas,rcar_sound-r8a77990" (R-Car E3)
+				    - "renesas,rcar_sound-r8a77995" (R-Car D3)
 - reg				: Should contain the register physical address.
 				  required register is
 				   SRU/ADG/SSI      if generation1