migration: No off-by-one for pss->page update in host page size

migration: No off-by-one for pss->page update in host page size

We used to do off-by-one fixup for pss->page when finished one host huge page
transfer.  That seems to be unnecesary at all.  Drop it.

Cc: Keqian Zhu <zhukeqian1@huawei.com>
Cc: Kunkun Jiang <jiangkunkun@huawei.com>
Cc: Andrey Gruzdev <andrey.gruzdev@virtuozzo.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>