PCI: Stop unhiding the SMBus on Toshiba laptops

It was found that the Toshiba laptops with hidden Intel SMBus have SMM
code handling the thermal management which accesses the SMBus. Thus it
is not safe to unhide it and let Linux access it. We have to leave the
SMBus hidden. SMM is a pain, really.

This fixes bugs #6315 and #6395, for good this time.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>