ARM: shmobile: switch SDHI0 to GPIO regulator on armadillo800eva

When regulators are used with MMC devices, explicitly provided OCR masks
are ignored, they can be removed from platform data. Also switch SDHI0
from fixed regulator with hard-wired GPIO levels to a proper GPIO regulator
instance to enable dynamic voltage switching.

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