dt-bindings: serial: sh-sci: Document r8a77961 bindings

Document support for the SCIF and HSCIF serial ports 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>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20191023123010.12501-1-geert+renesas@glider.beSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/serial/renesas,sci-serial.txt

@@ -54,8 +54,10 @@ Required properties:
     - "renesas,hscif-r8a7794" for R8A7794 (R-Car E2) HSCIF compatible UART.
     - "renesas,scif-r8a7795" for R8A7795 (R-Car H3) SCIF compatible UART.
     - "renesas,hscif-r8a7795" for R8A7795 (R-Car H3) HSCIF compatible UART.
-    - "renesas,scif-r8a7796" for R8A7796 (R-Car M3-W) SCIF compatible UART.
-    - "renesas,hscif-r8a7796" for R8A7796 (R-Car M3-W) HSCIF compatible UART.
+    - "renesas,scif-r8a7796" for R8A77960 (R-Car M3-W) SCIF compatible UART.
+    - "renesas,hscif-r8a7796" for R8A77960 (R-Car M3-W) HSCIF compatible UART.
+    - "renesas,scif-r8a77961" for R8A77961 (R-Car M3-W+) SCIF compatible UART.
+    - "renesas,hscif-r8a77961" for R8A77961 (R-Car M3-W+) HSCIF compatible UART.
     - "renesas,scif-r8a77965" for R8A77965 (R-Car M3-N) SCIF compatible UART.
     - "renesas,hscif-r8a77965" for R8A77965 (R-Car M3-N) HSCIF compatible UART.
     - "renesas,scif-r8a77970" for R8A77970 (R-Car V3M) SCIF compatible UART.