dt-bindings: watchdog: da9062: add suspend disable option

Document the watchdog disable option which can be used if the hardware
automatic suspend option is broken.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Reviewed-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200108095704.23233-3-m.felsch@pengutronix.de


Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>