RDS: Base init_depth and responder_resources on hw values

Instead of using a constant for initiator_depth and
responder_resources, read the per-QP values when the
device is enumerated, and then use these values when creating
the connection.

Signed-off-by: Andy Grover <andy.grover@oracle.com>

net/rds/ib.h

@@ -164,6 +164,8 @@ struct rds_ib_device {
 	unsigned int		max_fmrs;
 	int			max_sge;
 	unsigned int		max_wrs;
+	unsigned int		max_initiator_depth;
+	unsigned int		max_responder_resources;
 	spinlock_t		spinlock;	/* protect the above */
 };