ata: pata_parport: remove devtype from struct pi_adapter

Only bpck driver uses devtype but it never gets set in pata_parport.
Remove it.
As most bpck devices are CD-ROMs, always run the code that depends
on devtype == PI_PCD.

Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Ondrej Zary <linux@zary.sk>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>