iommu/vt-d: Remove incorrect PSI capability check

The PSI (Page Selective Invalidation) bit in the capability register
is only valid for second-level translation. Intel IOMMU supporting
scalable mode must support page/address selective IOTLB invalidation
for first-level translation. Remove the PSI capability check in SVA
cache invalidation code.

Fixes: 8744daf4 ("iommu/vt-d: Remove global page flush support")
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>