dt-bindings: serial: sh-sci: Document r8a7744 bindings

RZ/G1N (R8A7744) SoC also has the R-Car gen2 compatible SCIF, SCIFA,
SCIFB, and HSCIF ports, so document the SoC specific bindings.
Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Reviewed-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

@@ -14,6 +14,10 @@ Required properties:
     - "renesas,scifa-r8a7743" for R8A7743 (RZ/G1M) SCIFA compatible UART.
     - "renesas,scifb-r8a7743" for R8A7743 (RZ/G1M) SCIFB compatible UART.
     - "renesas,hscif-r8a7743" for R8A7743 (RZ/G1M) HSCIF compatible UART.
+    - "renesas,scif-r8a7744" for R8A7744 (RZ/G1N) SCIF compatible UART.
+    - "renesas,scifa-r8a7744" for R8A7744 (RZ/G1N) SCIFA compatible UART.
+    - "renesas,scifb-r8a7744" for R8A7744 (RZ/G1N) SCIFB compatible UART.
+    - "renesas,hscif-r8a7744" for R8A7744 (RZ/G1N) HSCIF compatible UART.
     - "renesas,scif-r8a7745" for R8A7745 (RZ/G1E) SCIF compatible UART.
     - "renesas,scifa-r8a7745" for R8A7745 (RZ/G1E) SCIFA compatible UART.
     - "renesas,scifb-r8a7745" for R8A7745 (RZ/G1E) SCIFB compatible UART.