iommu/exynos: Fix set_platform_dma_ops() callback

iommu/exynos: Fix set_platform_dma_ops() callback

There are some subtle differences between release_device() and
set_platform_dma_ops() callbacks, so separate those two callbacks. Device
links should be removed only in release_device(), because they were
created in probe_device() on purpose and they are needed for proper
Exynos IOMMU driver operation. While fixing this, remove the conditional
code as it is not really needed.

Reported-by: Jason Gunthorpe <jgg@ziepe.ca>
Fixes: 189d496b48b1 ("iommu/exynos: Add missing set_platform_dma_ops callback")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
Link: https://lore.kernel.org/r/20230315232514.1046589-1-m.szyprowski@samsung.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>