dt-bindings: mmc: renesas,mmcif: Document r8a7742 DT bindings

Add support for r8a7742 SoC. Renesas RZ/G1H (R8A7742) MMCIF is identical
to the R-Car Gen2 family.
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Marian-Cristian Rotariu <marian-cristian.rotariu.rb@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/1588794695-27852-2-git-send-email-prabhakar.mahadev-lad.rj@bp.renesas.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Documentation/devicetree/bindings/mmc/renesas,mmcif.txt

@@ -11,6 +11,7 @@ Required properties:
 	- "renesas,mmcif-r7s72100" for the MMCIF found in r7s72100 SoCs
 	- "renesas,mmcif-r8a73a4" for the MMCIF found in r8a73a4 SoCs
 	- "renesas,mmcif-r8a7740" for the MMCIF found in r8a7740 SoCs
+	- "renesas,mmcif-r8a7742" for the MMCIF found in r8a7742 SoCs
 	- "renesas,mmcif-r8a7743" for the MMCIF found in r8a7743 SoCs
 	- "renesas,mmcif-r8a7744" for the MMCIF found in r8a7744 SoCs
 	- "renesas,mmcif-r8a7745" for the MMCIF found in r8a7745 SoCs
@@ -24,8 +25,8 @@ Required properties:
 - interrupts: Some SoCs have only 1 shared interrupt, while others have either
   2 or 3 individual interrupts (error, int, card detect). Below is the number
   of interrupts for each SoC:
-    1: r8a73a4, r8a7743, r8a7744, r8a7745, r8a7778, r8a7790, r8a7791, r8a7793,
-       r8a7794
+    1: r8a73a4, r8a7742, r8a7743, r8a7744, r8a7745, r8a7778, r8a7790, r8a7791,
+       r8a7793, r8a7794
     2: r8a7740, sh73a0
     3: r7s72100