iommu/sun50i: Remove IOMMU_DOMAIN_IDENTITY

This driver treats IOMMU_DOMAIN_IDENTITY the same as UNMANAGED, which
cannot possibly be correct.

UNMANAGED domains are required to start out blocking all DMAs. This seems
to be what this driver does as it allocates a first level 'dt' for the IO
page table that is 0 filled.

Thus UNMANAGED looks like a working IO page table, and so IDENTITY must be
a mistake. Remove it.

Fixes: 4100b8c ("iommu: Add Allwinner H6 IOMMU driver")
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/0-v1-97f0adf27b5e+1f0-s50_identity_jgg@nvidia.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Author: jgunthorpe

drivers/iommu/sun50i-iommu.c

@@ -672,7 +672,6 @@ static struct iommu_domain *sun50i_iommu_domain_alloc(unsigned type)
 	struct sun50i_iommu_domain *sun50i_domain;
 
 	if (type != IOMMU_DOMAIN_DMA &&
-	    type != IOMMU_DOMAIN_IDENTITY &&
 	    type != IOMMU_DOMAIN_UNMANAGED)
 		return NULL;