sh-pfc: sh73a0: Add SDHI and MMCIF pin groups and functions

Add pin group definitions for SDHI0, SDHI1, SDHI2 and MMCIF interfaces on
sh73a0.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>