iommufd: Add capabilities to IOMMU_GET_HW_INFO

Extend IOMMUFD_CMD_GET_HW_INFO op to query generic iommu capabilities for a
given device.

Capabilities are IOMMU agnostic and use device_iommu_capable() API passing
one of the IOMMU_CAP_*. Enumerate IOMMU_CAP_DIRTY_TRACKING for now in the
out_capabilities field returned back to userspace.

Link: https://lore.kernel.org/r/20231024135109.73787-9-joao.m.martins@oracle.com


Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>