postcopy: Chunk discards for hugepages

postcopy: Chunk discards for hugepages

At the start of the postcopy phase, partially sent huge pages
must be discarded.  The code for dealing with host page sizes larger
than the target page size can be reused for this case.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Message-Id: <20170224182844.32452-4-dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>