xsm/flask: fix resource list range checks

xsm/flask: fix resource list range checks

The FLASK security checks for resource ranges were not implemented
correctly - only the permissions on the endpoints of a range were
checked, instead of all items contained in the range. This would allow
certain resources (I/O ports, I/O memory) to be used by domains in
contravention to security policy.

This also corrects a bug where adding overlapping resource ranges did
not trigger an error.

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