watchdog: qcom: register a restart notifier

The WDT's BITE_TIME warm-reset behavior can be leveraged as a last
resort mechanism for triggering chip reset.  Usually, other restart
methods (such as PS_HOLD) are preferrable for issuing a more complete
reset of the chip.  As such, keep the priority of the watchdog notifier
low.

Signed-off-by: Josh Cartwright <joshc@codeaurora.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>