net: mscc: ocelot: remove EXPORT_SYMBOL from ocelot_net.c

Now that all net_device operations are bundled together inside
mscc_ocelot.ko and no longer part of the common library, there's no
reason to export these symbols.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>