remoteproc: omap: 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()")
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Tested-by: Beleswar Padhi <b-padhi@ti.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/6186e311cb6f64a787f87fd41e49a73f409b789c.1730136799.git.robin.murphy@arm.com


[Fixed changelog title]
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>