ice: document RDMA devlink parameters

Commit e523af4ee560 ("net/ice: Add support for enable_iwarp and enable_roce
devlink param") added support for the enable_roce and enable_iwarp
parameters in the ice driver. It didn't document these parameters in the
ice devlink documentation file. Add this documentation, including a note
about the mutual exclusion between the two modes.

Signed-off-by: Jacob Keller <[e-mail]>
Reviewed-by: Leon Romanovsky <[e-mail]>
Acked-by: Tony Nguyen <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

Documentation/networking/devlink/ice.rst

···
 This document describes the devlink features implemented by the ``ice``
 device driver.
 
+Parameters
+==========
+
+.. list-table:: Generic parameters implemented
+
+   * - Name
+     - Mode
+     - Notes
+   * - ``enable_roce``
+     - runtime
+     - mutually exclusive with ``enable_iwarp``
+   * - ``enable_iwarp``
+     - runtime
+     - mutually exclusive with ``enable_roce``
+
 Info versions
 =============