RDMA/core: Add SRQ type field

Currently, there is only a single ("basic") type of SRQ, but with XRC
support we will add a second.  Prepare for this by defining an SRQ type
and setting all current users to IB_SRQT_BASIC.

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

drivers/infiniband/hw/mlx4/srq.c

@@ -81,6 +81,9 @@ struct ib_srq *mlx4_ib_create_srq(struct ib_pd *pd,
 	int err;
 	int i;
 
+	if (init_attr->srq_type != IB_SRQT_BASIC)
+		return ERR_PTR(-ENOSYS);
+
 	/* Sanity check SRQ size before proceeding */
 	if (init_attr->attr.max_wr  >= dev->dev->caps.max_srq_wqes ||
 	    init_attr->attr.max_sge >  dev->dev->caps.max_srq_sge)