RDMA/providers: Fix return value when QP type isn't supported

The proper return code is "-EOPNOTSUPP" when the requested QP type is
not supported by the provider.

Link: https://lore.kernel.org/r/20200130082049.463-1-kamalheib1@gmail.com
Signed-off-by: Kamal Heib <kamalheib1@gmail.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/cxgb4/qp.c

@@ -2127,7 +2127,7 @@ struct ib_qp *c4iw_create_qp(struct ib_pd *pd, struct ib_qp_init_attr *attrs,
 	pr_debug("ib_pd %p\n", pd);
 
 	if (attrs->qp_type != IB_QPT_RC)
-		return ERR_PTR(-EINVAL);
+		return ERR_PTR(-EOPNOTSUPP);
 
 	php = to_c4iw_pd(pd);
 	rhp = php->rhp;