xsm: Add security labels to event-channel dump

xsm: Add security labels to event-channel dump

In FLASK, event channel labels are distinct from the labels of the
domain using them. When debugging policy issues, it is useful to be
able to view the current label of event channels; add this label to
the event channel dump.

This patch also adds the IRQ associated with a PIRQ for event channels
bound to a PIRQ, and moves the xen_consumer flag to the front to
create more consistent alignment in the output.

Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Committed-by: Keir Fraser <keir@xen.org>