iommu/amd: Fix for pasid initialization

The pasid wasn't properly initialized before caling to invalid PPR calback

Signed-off-by: Alexey Skidanov <Alexey.Skidanov@amd.com>
Signed-off-by: Oded Gabbay <oded.gabbay@amd.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>