iommu/arm-smmu-v3: Remove domain_alloc_paging()

arm_smmu_domain_alloc_paging_flags() with a flags = 0 now does the same
thing as arm_smmu_domain_alloc_paging(), remove
arm_smmu_domain_alloc_paging().

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/3-v1-0bb8d5313a27+27b-smmuv3_paging_flags_jgg@nvidia.com


Signed-off-by: Will Deacon <will@kernel.org>