regulator: of: fix suspend-min/max-voltage parsing

Currently the regulator-suspend-min/max-microvolt must be within the
root regulator node but the dt-bindings specifies it as subnode
properties for the regulator-state-[mem/disk/standby] node. The only DT
using this bindings currently is the at91-sama5d2_xplained.dts and this
DT uses it correctly. I don't know if it isn't tested but it can't work
without this fix.

Fixes: f7efad10 ("regulator: add PM suspend and resume hooks")
Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Link: https://lore.kernel.org/r/20190917154021.14693-3-m.felsch@pengutronix.deSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/of_regulator.c

@@ -231,12 +231,12 @@ static int of_get_regulation_constraints(struct device *dev,
 					"regulator-off-in-suspend"))
 			suspend_state->enabled = DISABLE_IN_SUSPEND;
 
-		if (!of_property_read_u32(np, "regulator-suspend-min-microvolt",
-					  &pval))
+		if (!of_property_read_u32(suspend_np,
+				"regulator-suspend-min-microvolt", &pval))
 			suspend_state->min_uV = pval;
 
-		if (!of_property_read_u32(np, "regulator-suspend-max-microvolt",
-					  &pval))
+		if (!of_property_read_u32(suspend_np,
+				"regulator-suspend-max-microvolt", &pval))
 			suspend_state->max_uV = pval;
 
 		if (!of_property_read_u32(suspend_np,