pmdomain: renesas: rmobile-sysc: Don't keep unused PM domains powered-on

The recent changes to genpd makes a genpd OF provider that is powered-on at
initialization to stay powered-on, until the ->sync_state() callback is
invoked for it.

This may not happen at all, if we wait for a consumer device to be probed,
leading to wasting energy. There are ways to enforce the ->sync_state()
callback to be invoked, through sysfs or via the probe-defer-timeout, but
none of them in its current form are a good fit for rmobile-sysc PM
domains.

Let's therefore opt-out from this behaviour of genpd for now, by using the
GENPD_FLAG_NO_STAY_ON.

Link: https://lore.kernel.org/all/20250701114733.636510-1-ulf.hansson@linaro.org/
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Fixes: 0e789b4 ("pmdomain: core: Leave powered-on genpds on until sync_state")
Fixes: 13a4b7f ("pmdomain: core: Leave powered-on genpds on until late_initcall_sync")
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Author: storulf

drivers/pmdomain/renesas/rmobile-sysc.c

@@ -100,7 +100,8 @@ static void rmobile_init_pm_domain(struct rmobile_pm_domain *rmobile_pd)
 	struct generic_pm_domain *genpd = &rmobile_pd->genpd;
 	struct dev_power_governor *gov = rmobile_pd->gov;
 
-	genpd->flags |= GENPD_FLAG_PM_CLK | GENPD_FLAG_ACTIVE_WAKEUP;
+	genpd->flags |= GENPD_FLAG_PM_CLK | GENPD_FLAG_ACTIVE_WAKEUP |
+		GENPD_FLAG_NO_STAY_ON;
 	genpd->attach_dev = cpg_mstp_attach_dev;
 	genpd->detach_dev = cpg_mstp_detach_dev;