Documentation: devlink: add devlink documentation for the etas_es58x driver

List all the version information reported by the etas_es58x driver
through devlink. Also, update MAINTAINERS with the newly created file.

Signed-off-by: Vincent Mailhol <[e-mail]>
Link: https://lore.kernel.org/all/[e-mail]
[mkl: fixed version information table: "bl" -> "fw.bootloader"
Signed-off-by: Marc Kleine-Budde <[e-mail]>

Documentation/networking/devlink/etas_es58x.rst

···
+.. SPDX-License-Identifier: GPL-2.0
+
+==========================
+etas_es58x devlink support
+==========================
+
+This document describes the devlink features implemented by the
+``etas_es58x`` device driver.
+
+Info versions
+=============
+
+The ``etas_es58x`` driver reports the following versions
+
+.. list-table:: devlink info versions implemented
+   :widths: 5 5 90
+
+   * - Name
+     - Type
+     - Description
+   * - ``fw``
+     - running
+     - Version of the firmware running on the device. Also available
+       through ``ethtool -i`` as the first member of the
+       ``firmware-version``.
+   * - ``fw.bootloader``
+     - running
+     - Version of the bootloader running on the device. Also available
+       through ``ethtool -i`` as the second member of the
+       ``firmware-version``.
+   * - ``board.rev``
+     - fixed
+     - The hardware revision of the device.
+   * - ``serial_number``
+     - fixed
+     - The USB serial number. Also available through ``lsusb -v``.

MAINTAINERS

···
 M:	Vincent Mailhol <[e-mail]>
 L:	[e-mail]
 S:	Maintained
+F:	Documentation/networking/devlink/etas_es58x.rst
 F:	drivers/net/can/usb/etas_es58x/
 
 ETHERNET BRIDGE