hw/arm/smmuv3: Move reset to exit phase

hw/arm/smmuv3: Move reset to exit phase

Currently the iommu may be reset before the devices
it protects. For example this happens with virtio-scsi-pci.
when system_reset is issued from qmp monitor: spurious
"virtio: zero sized buffers are not allowed" warnings can
be observed. This happens because outstanding DMA requests
are still happening while the SMMU gets reset.

This can also happen with VFIO devices. In that case
spurious DMA translation faults can be observed on host.

Make sure the SMMU is reset in the 'exit' phase after
all DMA capable devices have been reset during the 'enter'
or 'hold' phase.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Message-Id: <20250218182737.76722-4-eric.auger@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>