[IB] CM: Fix initialization of QP attributes for UC QPs.

Fix cm_init_qp_init_attr(), cm_init_qp_rtr_attr() and cm_init_qp_rts_attr()
so that they correctly handle the differences between UC and RC QPs.  This
fixes problems with setting up UC QPs through the CM.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>