regulator: Assign return value of mc13xxx_reg_rmw to ret

Otherwise, we will not return error if write to MC13892_SWITCHERS5 failed.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Yong Shen <yong.shen@linaro.org>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>

drivers/regulator/mc13892-regulator.c

@@ -550,7 +550,7 @@ static int __devinit mc13892_regulator_probe(struct platform_device *pdev)
 		if (ret)
 			goto err_free;
 
-		mc13xxx_reg_rmw(mc13892, MC13892_SWITCHERS5,
+		ret = mc13xxx_reg_rmw(mc13892, MC13892_SWITCHERS5,
 			MC13892_SWITCHERS5_SW3MODE_M |
 			MC13892_SWITCHERS5_SW4MODE_M,
 			MC13892_SWITCHERS5_SW3MODE_AUTO |