watchdog: iTCO_wdt: Drop option vendorsupport=2

watchdog: iTCO_wdt: Drop option vendorsupport=2

iTCO_vendor_support's option vendorsupport=2 is a gross hack. It
claims to extend the existing iTCO_wdt driver, but in fact programs
a watchdog on a completely different device (Super-I/O) without
requesting its I/O ports and without checking the device ID. This is
an utterly dangerous thing to do.

It also turns out to be unnecessary, because as far as I can tell, the
code in question is basically duplicating what the clean w83627hf_wdt
driver is doing.

My guess is that on these SuperMicro boards which sparkled the
implementation of vendorsupport=2, the watchdog functionality of the
Intel south bridge is not used, and the watchdog feature of some
W83627HF-like Super-I/O chip is used instead. So we should point the
users to the w83627hf_wdt driver.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Martin Wilck <mwilck@suse.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>