pata_scc: add proper cable detection method

Use standard ata_cable_80wire() method for the cable detection,
as a bonus this allows us to use the default ->prereset method.

Acked-by: Kou Ishizaki <kou.ishizaki@toshiba.co.jp>
Acked-by: Akira Iguchi <akira2.iguchi@toshiba.co.jp>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>