parport_pc: detection for SuperIO IT87XX POST

Add detection for IT87XX SuperIO chip and disabling its POST feature, which
made noise on parallel port's pins.

Signed-off-by: Petr Cvek <petr.cvek@tul.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>