mmc: sh_mmcif: Document r8a73a4, r8a7778 and sh73a0 DT bindings

Simply document new compatibility strings as the driver is already
activated using a fallback compatibility string.

These compat strings are in keeping with those for all other
Renesas ARM based SoCs with sh_mmcif enabled in mainline.
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>
Acked-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

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

@@ -8,11 +8,14 @@ Required properties:
 
 - compatible: should be "renesas,mmcif-<soctype>", "renesas,sh-mmcif" as a
   fallback. Examples with <soctype> are:
+	- "renesas,mmcif-r8a73a4" for the MMCIF found in r8a73a4 SoCs
 	- "renesas,mmcif-r8a7740" for the MMCIF found in r8a7740 SoCs
+	- "renesas,mmcif-r8a7778" for the MMCIF found in r8a7778 SoCs
 	- "renesas,mmcif-r8a7790" for the MMCIF found in r8a7790 SoCs
 	- "renesas,mmcif-r8a7791" for the MMCIF found in r8a7791 SoCs
 	- "renesas,mmcif-r8a7793" for the MMCIF found in r8a7793 SoCs
 	- "renesas,mmcif-r8a7794" for the MMCIF found in r8a7794 SoCs
+	- "renesas,mmcif-sh73a0" for the MMCIF found in sh73a0 SoCs
 
 - clocks: reference to the functional clock