commit 6b7f000e upstream.

This function is called from enable_iommus(), which in turn is used
from amd_iommu_resume().
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>