watchdog: rzg2l_wdt: Make the driver depend on PM

The rzg2l_wdt watchdog driver cannot work w/o CONFIG_PM=y (e.g. the
clocks are enabled though pm_runtime_* specific APIs). To avoid building
a driver that doesn't work make explicit the dependency on CONFIG_PM.

Suggested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20240531065723.1085423-3-claudiu.beznea.uj@bp.renesas.com


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