ARM: shmobile: mackerel: add interrupt names for SDHI0

To unify with SDHI1 also use named IRQs for SDHI0. This also clarifies
which specific IRQs are used.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@gmail.com>
Acked-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>