avr32: don't offer PARPORT_PC

This patch fixes the following compile error:

<--  snip  -->

...
  CC [M]  drivers/parport/parport_pc.o
/home/bunk/linux/kernel-2.6/git/linux-2.6/drivers/parport/parport_pc.c:67:25: error: asm/parport.h: No such file or directory
/home/bunk/linux/kernel-2.6/git/linux-2.6/drivers/parport/parport_pc.c: In function 'parport_pc_find_ports':
/home/bunk/linux/kernel-2.6/git/linux-2.6/drivers/parport/parport_pc.c:3215: error: implicit declaration of function 'parport_pc_find_nonpci_ports'
make[3]: *** [drivers/parport/parport_pc.o] Error 1

<--  snip  -->

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>