DT: serial: renesas,sci-serial: document R8A77980 bindings

R-Car V3H (R8A77980) SoC has the R-Car gen3 compatible SCIF and HSCIF ports,
so document the SoC specific bindings.
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Reviewed-by: NRob Herring <robh@kernel.org>
Reviewed-by: NSimon Horman <horms+renesas@verge.net.au>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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

@@ -43,6 +43,8 @@ Required properties:
     - "renesas,hscif-r8a7796" for R8A7796 (R-Car M3-W) HSCIF compatible UART.
     - "renesas,scif-r8a77970" for R8A77970 (R-Car V3M) SCIF compatible UART.
     - "renesas,hscif-r8a77970" for R8A77970 (R-Car V3M) HSCIF compatible UART.
+    - "renesas,scif-r8a77980" for R8A77980 (R-Car V3H) SCIF compatible UART.
+    - "renesas,hscif-r8a77980" for R8A77980 (R-Car V3H) HSCIF compatible UART.
     - "renesas,scif-r8a77995" for R8A77995 (R-Car D3) SCIF compatible UART.
     - "renesas,hscif-r8a77995" for R8A77995 (R-Car D3) HSCIF compatible UART.
     - "renesas,scifa-sh73a0" for SH73A0 (SH-Mobile AG5) SCIFA compatible UART.