iommu/vt-d: Cleanup use of iommu_flush_iotlb_psi()

iommu/vt-d: Cleanup use of iommu_flush_iotlb_psi()

Use cache_tag_flush_range() in switch_to_super_page() to invalidate the
necessary caches when switching mappings from normal to super pages. The
iommu_flush_iotlb_psi() call in intel_iommu_memory_notifier() is
unnecessary since there should be no cache invalidation for the identity
domain.

Clean up iommu_flush_iotlb_psi() after the last call site is removed.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20240416080656.60968-8-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>