mmc: renesas_sdhi: Add r8a77990 support

This patch adds SDHI support for the R8A77990 SoC (R-Car E3). No driver changes
needed for anything except HS400 which we will enable separately later.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Documentation/devicetree/bindings/mmc/tmio_mmc.txt

@@ -28,6 +28,7 @@ Required properties:
 		"renesas,sdhi-r8a7796" - SDHI IP on R8A7796 SoC
 		"renesas,sdhi-r8a77965" - SDHI IP on R8A77965 SoC
 		"renesas,sdhi-r8a77980" - SDHI IP on R8A77980 SoC
+		"renesas,sdhi-r8a77990" - SDHI IP on R8A77990 SoC
 		"renesas,sdhi-r8a77995" - SDHI IP on R8A77995 SoC
 		"renesas,sdhi-shmobile" - a generic sh-mobile SDHI controller
 		"renesas,rcar-gen1-sdhi" - a generic R-Car Gen1 SDHI controller