m68k/mac: Export Peripheral System Controller (PSC) base address to modules

If CONFIG_MACMACE=m:

    ERROR: psc [drivers/net/ethernet/apple/macmace.ko] undefined!

Add the missing export to fix this.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: David S. Miller <davem@davemloft.net>