PM: domains: log failures to register always-on domains

Always-on PM domains must be on during initialisation or the domain is
currently silently rejected.

Print an error message in case an always-on domain is not on to make it
easier to debug drivers getting this wrong (e.g. by setting an always-on
genpd flag without making sure that the state matches).

Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/base/power/domain.c

@@ -2085,8 +2085,10 @@ int pm_genpd_init(struct generic_pm_domain *genpd,
 
 	/* Always-on domains must be powered on at initialization. */
 	if ((genpd_is_always_on(genpd) || genpd_is_rpm_always_on(genpd)) &&
-			!genpd_status_on(genpd))
+			!genpd_status_on(genpd)) {
+		pr_err("always-on PM domain %s is not on\n", genpd->name);
 		return -EINVAL;
+	}
 
 	/* Multiple states but no governor doesn't make sense. */
 	if (!gov && genpd->state_count > 1)