leds: lp5521: Fix return value

Return the value obtained from i2c_smbus_read_byte_data() instead of
-EIO. Silences the following smatch warning:
drivers/leds/leds-lp5521.c:155 lp5521_read() info:
why not propagate 'ret' from i2c_smbus_read_byte_data() instead of -5?
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NBryan Wu <cooloney@gmail.com>

drivers/leds/leds-lp5521.c

@@ -152,7 +152,7 @@ static int lp5521_read(struct i2c_client *client, u8 reg, u8 *buf)
 
 	ret = i2c_smbus_read_byte_data(client, reg);
 	if (ret < 0)
-		return -EIO;
+		return ret;
 
 	*buf = ret;
 	return 0;