arm64: Properly clean up iommu-dma remnants

Thanks to the somewhat asymmetrical nature, while removing
iommu_setup_dma_ops() from the arch_setup_dma_ops() flow, I managed to
forget that arm64's teardown path was also specific to iommu-dma. Clean
that up to match, otherwise probe deferral will lead to the arch code
erroneously removing DMA ops set elsewhere.
Reported-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/linux-iommu/Zi_LV28TR-P-PzXi@eriador.lumag.spb.ru/
Fixes: b67483b3 ("iommu/dma: Centralise iommu_setup_dma_ops()")
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Tested-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Acked-by: Will Deacon <will@kernel.org>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Link: https://lore.kernel.org/r/d4cc20cbb0c45175e98dd76bf187e2ad6421296d.1714472573.git.robin.murphy@arm.comSigned-off-by: Joerg Roedel <jroedel@suse.de>

arch/arm64/Kconfig

@@ -46,7 +46,6 @@ config ARM64
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
 	select ARCH_HAS_SYNC_DMA_FOR_CPU
 	select ARCH_HAS_SYSCALL_WRAPPER
-	select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_SUPPORT
 	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
 	select ARCH_HAS_ZONE_DMA_SET if EXPERT
 	select ARCH_HAVE_ELF_PROT

arch/arm64/mm/dma-mapping.c

@@ -7,7 +7,6 @@
 #include <linux/gfp.h>
 #include <linux/cache.h>
 #include <linux/dma-map-ops.h>
-#include <linux/iommu.h>
 #include <xen/xen.h>
 
 #include <asm/cacheflush.h>
@@ -39,13 +38,6 @@ void arch_dma_prep_coherent(struct page *page, size_t size)
 	dcache_clean_poc(start, start + size);
 }
 
-#ifdef CONFIG_IOMMU_DMA
-void arch_teardown_dma_ops(struct device *dev)
-{
-	dev->dma_ops = NULL;
-}
-#endif
-
 void arch_setup_dma_ops(struct device *dev, bool coherent)
 {
 	int cls = cache_line_size_of_cpu();