devlink: add a driver-specific file for the qed driver

The qed driver recently added devlink support with a single devlink
parameter. Add a driver-specific file to document the devlink features
that the qed driver supports.
Signed-off-by: NJacob Keller <jacob.e.keller@intel.com>
Cc: Ariel Elior <aelior@marvell.com>
Cc: GR-everest-linux-l2@marvell.com
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Documentation/networking/devlink/index.rst

@@ -34,4 +34,5 @@ parameters, info versions, and other features it supports.
    mlxsw
    mv88e6xxx
    nfp
+   qed
    ti-cpsw-switch

Documentation/networking/devlink/qed.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+===================
+qed devlink support
+===================
+
+This document describes the devlink features implemented by the ``qed`` core
+device driver.
+
+Parameters
+==========
+
+The ``qed`` driver implements the following driver-specific parameters.
+
+.. list-table:: Driver-specific parameters implemented
+   :widths: 5 5 5 85
+
+   * - Name
+     - Type
+     - Mode
+     - Description
+   * - ``iwarp_cmt``
+     - Boolean
+     - runtime
+     - Enable iWARP functionality for 100g devices. Notee that this impacts
+       L2 performance, and is therefor not enabled by default.