regulator: tps65218: force set power-up/down strobe to 3 for dcdc3

The reset value for this register seems broken on certain versions of
tps65218 chip, so make sure the dcdc3 settings is proper. Needed for
proper functionality of rtc+ddr / rtc-only modes.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Signed-off-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/drivers/regulator/tps65218-regulator.c b/drivers/regulator/tps65218-regulator.c
index 8eca1eb..d1e631d 100644
--- a/drivers/regulator/tps65218-regulator.c
+++ b/drivers/regulator/tps65218-regulator.c
@@ -180,8 +180,12 @@
 	if (rid < TPS65218_DCDC_1 || rid > TPS65218_LDO_1)
 		return -EINVAL;
 
-	if (!tps->info[rid]->strobe)
-		return -EINVAL;
+	if (!tps->info[rid]->strobe) {
+		if (rid == TPS65218_DCDC_3)
+			tps->info[rid]->strobe = 3;
+		else
+			return -EINVAL;
+	}
 
 	return tps65218_set_bits(tps, dev->desc->bypass_reg,
 				 dev->desc->bypass_mask,