iommu/amd: Call domain_flush_complete() in update_domain()

The update_domain() function is expected to also inform the hardware
about domain changes. This needs a COMPLETION_WAIT command to be sent
to all IOMMUs which use the domain.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Tested-by: Qian Cai <cai@lca.pw>
Link: https://lore.kernel.org/r/20200504125413.16798-4-joro@8bytes.org


Signed-off-by: Joerg Roedel <jroedel@suse.de>