ARM: shmobile: kzm9g: SDHI0 and SDHI1 use a 3.3V power supply

kzm9g supplies 3.3V to its SDHI0 and SDHI2 interfaces. Specifying 2.8V
prevents some (e.g. certain SDIO) cards from working. This patch fixes the
voltage and removes redundant OCR masks from platform data.

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