charger-manager: Fix regulator_get() return check

This patch fixes return value checking of regulator_get() in
charger-manager driver. The API, regulator_get(), returns ERR_PTR() when
it fails to get regulator with given name, not NULL.
Signed-off-by: Jonghwa Lee <jonghwa3.lee@samsung.com>
Signed-off-by: Myungjoo Ham <myungjoo.ham@samsung.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Anton Vorontsov <anton@enomsg.org>

drivers/power/charger-manager.c

@@ -1239,11 +1239,10 @@ static int charger_manager_register_extcon(struct charger_manager *cm)
 
 		charger->consumer = regulator_get(cm->dev,
 					charger->regulator_name);
-		if (charger->consumer == NULL) {
+		if (IS_ERR(charger->consumer)) {
 			dev_err(cm->dev, "Cannot find charger(%s)\n",
 				charger->regulator_name);
-			ret = -EINVAL;
-			goto err;
+			return PTR_ERR(charger->consumer);
 		}
 		charger->cm = cm;