[infiniband] Add infrastructure for RC queue pairs

Queue pairs are now assumed to be created in the INIT state, with a
call to ib_modify_qp() required to bring the queue pair to the RTS
state.

ib_modify_qp() no longer takes a modification list; callers should
modify the relevant queue pair parameters (e.g. qkey) directly and
then call ib_modify_qp() to synchronise the changes to the hardware.

The packet sequence number is now a property of the queue pair, rather
than of the device.

Each queue pair may have an associated address vector.  For RC queue
pairs, this is the address vector that will be programmed in to the
hardware as the remote address.  For UD queue pairs, it will be used
as the default address vector if none is supplied to ib_post_send().

src/drivers/net/ipoib.c

@@ -521,7 +521,7 @@ static int ipoib_open ( struct net_device *netdev ) {
 	/* Allocate queue pair */
 	ipoib->qp = ib_create_qp ( ibdev, IB_QPT_UD,
 				   IPOIB_NUM_SEND_WQES, ipoib->cq,
-				   IPOIB_NUM_RECV_WQES, ipoib->cq, 0 );
+				   IPOIB_NUM_RECV_WQES, ipoib->cq );
 	if ( ! ipoib->qp ) {
 		DBGC ( ipoib, "IPoIB %p could not allocate queue pair\n",
 		       ipoib );