iommu/arm-smmu: Remove iommu_ops pgsize_bitmap

iommu/arm-smmu: Remove iommu_ops pgsize_bitmap

The driver never reads this value, arm_smmu_init_domain_context() always
sets domain.pgsize_bitmap to smmu->pgsize_bitmap, the per-instance value.

Remove the ops version entirely, the related dead code and make
arm_smmu_ops const.

Since this driver does not yet finalize the domain under
arm_smmu_domain_alloc_paging() add a page size initialization to alloc so
the page size is still setup prior to attach.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Link: https://lore.kernel.org/r/2-v2-68a2e1ba507c+1fb-iommu_rm_ops_pgsize_jgg@nvidia.com
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>