iommu/vt-d: Remove private data use in fault message

iommu/vt-d: Remove private data use in fault message

According to Intel VT-d specification revision 4.0, "Private Data"
field has been removed from Page Request/Response.

Since the private data field is not used in fault message, remove the
related definitions in page request descriptor and remove the related
code in page request/response handler, as Intel hasn't shipped any
products which support private data in the page request message.

Signed-off-by: Jingqi Liu <Jingqi.liu@intel.com>
Link: https://lore.kernel.org/r/20240308103811.76744-3-Jingqi.liu@intel.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>