soc: mediatek: Check if power domains can be powered on at boot time

In the error case, where a power domain cannot be powered on
successfully at boot time (in mtk_register_power_domains),
pm_genpd_init would still be called with is_off=false, and the
system would later try to disable the power domain again, triggering
warnings as disabled clocks are disabled again (and other potential
issues).

Also print a warning splat in that case, as this should never
happen.

Fixes: c84e3587 ("soc: Mediatek: Add SCPSYS power domain driver")
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Link: https://lore.kernel.org/r/20200928113107.v2.1.I5e6f8c262031d0451fe7241b744f4f3111c1ce71@changeidSigned-off-by: Matthias Brugger <matthias.bgg@gmail.com>

drivers/soc/mediatek/mtk-scpsys.c

@@ -524,6 +524,7 @@ static void mtk_register_power_domains(struct platform_device *pdev,
 	for (i = 0; i < num; i++) {
 		struct scp_domain *scpd = &scp->domains[i];
 		struct generic_pm_domain *genpd = &scpd->genpd;
+		bool on;
 
 		/*
 		 * Initially turn on all domains to make the domains usable
@@ -531,9 +532,9 @@ static void mtk_register_power_domains(struct platform_device *pdev,
 		 * software.  The unused domains will be switched off during
 		 * late_init time.
 		 */
-		genpd->power_on(genpd);
+		on = !WARN_ON(genpd->power_on(genpd) < 0);
 
-		pm_genpd_init(genpd, NULL, false);
+		pm_genpd_init(genpd, NULL, !on);
 	}
 
 	/*