f969bc9fc9 forbid get_address_size call on HVM guests, because that
didn't make sense. It broke core dump functionality on HVM because
libxc unconditionally asked for guest width.
Force guest_width to a sensible value.
Reported-by: Igor Druzhinin <igor.druzhinin@citrix.com>
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>