media: omap3isp: Handle ARM dma_iommu_mapping

It's no longer practical for the OMAP IOMMU driver to trick
arm_setup_iommu_dma_ops() into ignoring its presence, so let's use the
same tactic as other IOMMU API users on 32-bit ARM and explicitly kick
the arch code's dma_iommu_mapping out of the way to avoid problems.

Fixes: 4720287c ("iommu: Remove struct iommu_ops *iommu from arch_setup_dma_ops()")
Cc: stable@vger.kernel.org
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Tested-by: Sicelo A. Mhlongo <absicsz@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>