iommu/vt-d: Add PASID_FLAG_FL5LP for first-level pasid setup

Current intel_pasid_setup_first_level() use 5-level paging for
first level translation if CPUs use 5-level paging mode too.
This makes sense for SVA usages since the page table is shared
between CPUs and IOMMUs. But it makes no sense if we only want
to use first level for IOVA translation. Add PASID_FLAG_FL5LP
bit in the flags which indicates whether the 5-level paging
mode should be used.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>