iommu/amd: Do not set amd_iommu_pgtable in pass-through mode

Since AMD IOMMU page table is not used in passthrough mode, switching to
v1 page table is not required.

Therefore, remove redundant amd_iommu_pgtable update and misleading
warning message.

Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Link: https://lore.kernel.org/r/20230921092147.5930-7-vasant.hegde@amd.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Author: hegdevasant

drivers/iommu/amd/init.c

@@ -2134,9 +2134,6 @@ static int __init iommu_init_pci(struct amd_iommu *iommu)
 		    !iommu_feature(iommu, FEATURE_GT)) {
 			pr_warn("Cannot enable v2 page table for DMA-API. Fallback to v1.\n");
 			amd_iommu_pgtable = AMD_IOMMU_V1;
-		} else if (iommu_default_passthrough()) {
-			pr_warn("V2 page table doesn't support passthrough mode. Fallback to v1.\n");
-			amd_iommu_pgtable = AMD_IOMMU_V1;
 		}
 	}