iommu/vt-d: Check UAPI data processed by IOMMU core

IOMMU generic layer already does sanity checks on UAPI data for version
match and argsz range based on generic information.

This patch adjusts the following data checking responsibilities:
- removes the redundant version check from VT-d driver
- removes the check for vendor specific data size
- adds check for the use of reserved/undefined flags

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Link: https://lore.kernel.org/r/1601051567-54787-7-git-send-email-jacob.jun.pan@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>