watchdog: bcm2835_wdt: Switch to new sys-off handler API

watchdog: bcm2835_wdt: Switch to new sys-off handler API

Kernel now supports chained power-off handlers. Use
devm_register_sys_off_handler() that registers a power-off handler. Legacy
pm_power_off() will be removed once all drivers and archs are converted to
the new sys-off API.

Signed-off-by: Andrew Davis <afd@ti.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://lore.kernel.org/r/20260302180853.224112-1-afd@ti.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>