iommu/amd: Make sure IOMMU interrupts are re-enabled on resume

iommu/amd: Make sure IOMMU interrupts are re-enabled on resume

BugLink: http://bugs.launchpad.net/bugs/981162

commit 9ddd592a191b32f2ee6c4b6ed2bd52665c3a49f5 upstream

Unfortunatly the interrupts for the event log and the
peripheral page-faults are only enabled at boot but not
re-enabled at resume. Fix that for 3.2.

Cc: stable@vger.kernel.org
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Leann Ogasawara <leann.ogasawara@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>