net: mscc: ocelot: remove redundant stats_layout pointers

Ever since commit 4d1d157f

 ("net: mscc: ocelot: share the common stat
definitions between all drivers") the stats_layout entry in ocelot and
felix drivers have become redundant. Remove the unnecessary code.

Suggested-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>