net: sparx5: modify SPX5_PORTS_ALL macro

In preparation for lan969x, we need to define the SPX5_PORTS_ALL macro
as 70 (65 front ports + 5 internal ports). This is required as the
SPX5_PORT_CPU will be redefined as an offset to the number of front
ports, in a subsequent patch.

Reviewed-by: Steen Hegelund <Steen.Hegelund@microchip.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Daniel Machon <daniel.machon@microchip.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>