staging/rdma/hfi1: move hfi1_migrate_qp

Move hfi1_migrate_qp from ruc.c to qp.[hc] in prep for modifying the QP
workqueue.

Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>