iommu/arm-smmu-v3-iommufd: Add vsmmu_size/type and vsmmu_init impl ops

iommu/arm-smmu-v3-iommufd: Add vsmmu_size/type and vsmmu_init impl ops

An impl driver might want to allocate its own type of vIOMMU object or the
standard IOMMU_VIOMMU_TYPE_ARM_SMMUV3 by setting up its own SW/HW bits, as
the tegra241-cmdqv driver will add IOMMU_VIOMMU_TYPE_TEGRA241_CMDQV.

Add vsmmu_size/type and vsmmu_init to struct arm_smmu_impl_ops. Prioritize
them in arm_smmu_get_viommu_size() and arm_vsmmu_init().

Link: https://patch.msgid.link/r/375ac2b056764534bb7c10ecc4f34a0bae82b108.1752126748.git.nicolinc@nvidia.com
Reviewed-by: Pranjal Shrivastava <praan@google.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>