intel-iommu: trace domain id during page walk

This patch only modifies the trace points.

Previously we were tracing page walk levels.  They are redundant since
we have page mask (size) already.  Now we trace something much more
useful which is the domain ID of the page walking.  That can be very
useful when we trace more than one devices on the same system, so that
we can know which map is for which domain.

CC: QEMU Stable <qemu-stable@nongnu.org>
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>