iommu/arm-smmu-v3: Use device properties for pasid-num-bits

iommu/arm-smmu-v3: Use device properties for pasid-num-bits

The pasid-num-bits property shouldn't need a dedicated fwspec field,
it's a job for device properties. Add properties for IORT, and access
the number of PASID bits using device_property_read_u32().

Suggested-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Acked-by: Hanjun Guo <guohanjun@huawei.com>
Link: https://lore.kernel.org/r/20210401154718.307519-3-jean-philippe@linaro.org
Signed-off-by: Joerg Roedel <jroedel@suse.de>