If unsigned the watchdog_trigger() return value will not be
checked correctly.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com> Acked-by: Andrew Morton <akpm@linux-foundation.org> Cc: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Jean Delvare <khali@linux-fr.org>