iommu/vt-d: Add definitions for PFSID

When SRIOV VF device IOTLB is invalidated, we need to provide
the PF source ID such that IOMMU hardware can gauge the depth
of invalidation queue which is shared among VFs. This is needed
when device invalidation throttle (DIT) capability is supported.

This patch adds bit definitions for checking and tracking PFSID.

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: stable@vger.kernel.org
Cc: "Ashok Raj" <ashok.raj@intel.com>
Cc: "Lu Baolu" <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>