iommu/amd: Remove the amd_iommu_domain_set_pt_root() and related

iommu/amd: Remove the amd_iommu_domain_set_pt_root() and related

Looks like many refactorings here have left this confused. There is only
one storage of the root/mode, it is in the iop struct.

increase_address_space() calls amd_iommu_domain_set_pgtable() with values
that it already stored in iop a few lines above.

amd_iommu_domain_clr_pt_root() is zero'ing memory we are about to free. It
used to protect against a double free of root, but that is gone now.

Remove amd_iommu_domain_set_pgtable(), amd_iommu_domain_set_pt_root(),
amd_iommu_domain_clr_pt_root() as they are all pointless.

Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/5-v2-831cdc4d00f3+1a315-amd_iopgtbl_jgg@nvidia.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>