net: mscc: ocelot: rename ocelot_board.c to ocelot_vsc7514.c

To follow the model of felix and seville where we have one
platform-specific file, rename this file to the actual SoC it serves.

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