ARM: shmobile: r8a7790: add MMCIF and SDHI DT templates

This adds DT templates for all MMCIF and SDHI controllers on r8a7790.
They are added with status="disabled". To use them platform-specific
DTs have to enable the required ones.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@gmail.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>