Bind OMAP3's isp device to the isp's dedicated iommu, by setting
the device's archdata iommu member.

This way omap3isp will be able to use the generic IOMMU API without
having to call any omap-specific binding method.
Signed-off-by: NOhad Ben-Cohen <ohad@wizery.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: NTony Lindgren <tony@atomide.com>