devlink: Add new "event_eq_size" generic device param

Add new device generic parameter to determine the size of the
asynchronous control events EQ.

For example, to reduce event EQ size to 64, execute:
$ devlink dev param set pci/0000:06:00.0 \
              name event_eq_size value 64 cmode driverinit
$ devlink dev reload pci/0000:06:00.0

Signed-off-by: Shay Drory <shayd@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

Documentation/networking/devlink/devlink-params.rst

@@ -132,3 +132,6 @@ own name.
    * - ``io_eq_size``
      - u32
      - Control the size of I/O completion EQs.
+   * - ``event_eq_size``
+     - u32
+     - Control the size of asynchronous control events EQ.