iommu/arm-smmu-v3: Add acpi_smmu_iort_probe_model for impl

For model-specific implementation, repurpose the acpi_smmu_get_options()
to a wider acpi_smmu_acpi_probe_model(). A new model can add to the list
in this new function.

Suggested-by: Will Deacon <will@kernel.org>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Link: https://lore.kernel.org/r/79716299829aeab2e55b8c7932f2634b209bb4d5.1724970714.git.nicolinc@nvidia.com


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