regulator: max14577: Add error check for max14577_read_reg()

The function max14577_reg_get_current_limit() calls the function
max14577_read_reg(), but does not check its return value. A proper
implementation can be found in max14577_get_online().

Add a error check for the max14577_read_reg() and return error code
if the function fails.

Fixes: b0902bb ("regulator: max14577: Add regulator driver for Maxim 14577")
Cc: stable@vger.kernel.org # v3.14
Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
Link: https://patch.msgid.link/20250526025627.407-1-vulab@iscas.ac.cn
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: ISCAS-Vulab

drivers/regulator/max14577-regulator.c

@@ -40,11 +40,14 @@ static int max14577_reg_get_current_limit(struct regulator_dev *rdev)
 	struct max14577 *max14577 = rdev_get_drvdata(rdev);
 	const struct maxim_charger_current *limits =
 		&maxim_charger_currents[max14577->dev_type];
+	int ret;
 
 	if (rdev_get_id(rdev) != MAX14577_CHARGER)
 		return -EINVAL;
 
-	max14577_read_reg(rmap, MAX14577_CHG_REG_CHG_CTRL4, &reg_data);
+	ret = max14577_read_reg(rmap, MAX14577_CHG_REG_CHG_CTRL4, &reg_data);
+	if (ret < 0)
+		return ret;
 
 	if ((reg_data & CHGCTRL4_MBCICHWRCL_MASK) == 0)
 		return limits->min;