dt-bindings: i2c: rcar: Document r8a77961 support

Document support for the I2C controller in the Renesas R-Car M3-W+
(R8A77961) SoC.

Update all references to R-Car M3-W from "r8a7796" to "r8a77960", to
avoid confusion between R-Car M3-W (R8A77960) and M3-W+.

No driver update is needed.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Documentation/devicetree/bindings/i2c/renesas,i2c.txt

@@ -17,7 +17,8 @@ Required properties:
 	"renesas,i2c-r8a7793" if the device is a part of a R8A7793 SoC.
 	"renesas,i2c-r8a7794" if the device is a part of a R8A7794 SoC.
 	"renesas,i2c-r8a7795" if the device is a part of a R8A7795 SoC.
-	"renesas,i2c-r8a7796" if the device is a part of a R8A7796 SoC.
+	"renesas,i2c-r8a7796" if the device is a part of a R8A77960 SoC.
+	"renesas,i2c-r8a77961" if the device is a part of a R8A77961 SoC.
 	"renesas,i2c-r8a77965" if the device is a part of a R8A77965 SoC.
 	"renesas,i2c-r8a77970" if the device is a part of a R8A77970 SoC.
 	"renesas,i2c-r8a77980" if the device is a part of a R8A77980 SoC.