RDMA/nes: Fix slab corruption

Referencing cm_node after it is freed via rem_ref_cm_node() causes a
slab corruption.  There is no need to set cm_node->cm_id to NULL in
mini_cm_close().
Signed-off-by: NChien Tung <ctung@neteffect.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/nes/nes_cm.c

@@ -2029,7 +2029,6 @@ static int mini_cm_close(struct nes_cm_core *cm_core, struct nes_cm_node *cm_nod
 		ret = rem_ref_cm_node(cm_core, cm_node);
 		break;
 	}
-	cm_node->cm_id = NULL;
 	return ret;
 }