[PATCH] libata: rename ATA_FLAG_PORT_DISABLED to ATA_FLAG_DISABLED

Rename ATA_FLAG_PORT_DISABLED to ATA_FLAG_DISABLED for consistency.
(ATA_FLAG_* are always about ports).

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>