[media] omap3isp: Replace many MMIO regions by two

The omap3isp MMIO register block is contiguous in the MMIO register space
apart from the fact that the ISP IOMMU register block is in the middle of
the area. Ioremap it at two occasions, and keep the rest of the layout of
the register space internal to the omap3isp driver.

Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>