dt-bindings: serial: sh-sci: Document r8a7778/9 HSCIF bindings

Document support for the HSCIF serial ports in the Renesas R-Car M1A
(R8A7778) and H1 (R8A7779) SoCs.

No driver update is needed.
Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
[geert: Patch description]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rob Herring <robh@kernel.org>

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

@@ -29,7 +29,9 @@ Required properties:
     - "renesas,scif-r8a774c0" for R8A774C0 (RZ/G2E) SCIF compatible UART.
     - "renesas,hscif-r8a774c0" for R8A774C0 (RZ/G2E) HSCIF compatible UART.
     - "renesas,scif-r8a7778" for R8A7778 (R-Car M1) SCIF compatible UART.
+    - "renesas,hscif-r8a7778" for R8A7778 (R-Car M1) HSCIF compatible UART.
     - "renesas,scif-r8a7779" for R8A7779 (R-Car H1) SCIF compatible UART.
+    - "renesas,hscif-r8a7779" for R8A7779 (R-Car H1) HSCIF compatible UART.
     - "renesas,scif-r8a7790" for R8A7790 (R-Car H2) SCIF compatible UART.
     - "renesas,scifa-r8a7790" for R8A7790 (R-Car H2) SCIFA compatible UART.
     - "renesas,scifb-r8a7790" for R8A7790 (R-Car H2) SCIFB compatible UART.