ARM: shmobile: r8a7790: add clock definitions and aliases for MMCIF and SDHI

Add MSTP clock definitions and fix aliases for the two MMCIF and four SDHI
interfaces on r8a7790 (H2).

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