iommu/arm-smmu-v3: Replace vsmmu_size/type with get_viommu_size

It's more flexible to have a get_viommu_size op. Replace static vsmmu_size
and vsmmu_type with that.

Link: https://patch.msgid.link/r/20250724221002.1883034-3-nicolinc@nvidia.com


Suggested-by: Will Deacon <will@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Pranjal Shrivastava <praan@google.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>