power: reset: msm-poweroff: Use devm_register_sys_off_handler(RESTART)

Use device life-cycle managed register function to simplify probe.

Signed-off-by: Andrew Davis <afd@ti.com>
Link: https://lore.kernel.org/r/20240212162831.67838-14-afd@ti.com


Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>