watchdog: hpwdt: Disable PreTimeout when Timeout is smaller

During module install, disable pretimeout if the requested timeout
value is not greater than the minimal pretimeout value that is
supported by hardware.

This makes the module load handling of pretimeout consistent
with the ioctl handling of pretimeout.

Signed-off-by: Jerry Hoemann <jerry.hoemann@hpe.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>