iommu: Add generic PASID table library

hulk inclusion
category: feature
bugzilla: 14369
CVE: NA
-------------------

Add a small API within the IOMMU subsystem to handle different formats of
PASID tables. It uses the same principle as io-pgtable:

* The IOMMU driver registers a PASID table with some invalidation
  callbacks.
* The pasid-table lib allocates a set of tables of the right format, and
  returns an iommu_pasid_table_ops structure.
* The IOMMU driver allocates entries and writes them using the provided
  ops.
* The pasid-table lib calls the IOMMU driver back for invalidation when
  necessary.
* The IOMMU driver unregisters the ops which frees the tables when
  finished.

An example user will be Arm SMMU in a subsequent patch. Other IOMMU
drivers (e.g. paravirtualized ones) will be able to use the same PASID
table code.

Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: Fang Lijun <fanglijun3@huawei.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Reviewed-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>