ARM: mach-shmobile: add SDHI2 to the 2.8V fixed regulator consumers on kzm9g

The recently added SDHI2 interface to kzm9g needs power supplies for the
upcoming transition away from OCR masks, provided in platform data.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>