iio: max9611: Use sysfs_emit()

sysfs_emit() is preferred over raw s*printf() for sysfs attributes since it
knows about the sysfs buffer specifics and has some built-in checks for
size and alignment.

Use sysfs_emit() to format the custom `in_power_shunt_resistor` and
`in_current_shunt_resistor` device attributes of the max9611 driver.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Link: https://lore.kernel.org/r/20211216185217.1054495-11-lars@metafoo.deSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/max9611.c

@@ -429,7 +429,7 @@ static ssize_t max9611_shunt_resistor_show(struct device *dev,
 	i = max9611->shunt_resistor_uohm / 1000000;
 	r = max9611->shunt_resistor_uohm % 1000000;
 
-	return sprintf(buf, "%u.%06u\n", i, r);
+	return sysfs_emit(buf, "%u.%06u\n", i, r);
 }
 
 static IIO_DEVICE_ATTR(in_power_shunt_resistor, 0444,