iio: ms_sensors: 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 `battery_low` and `heater_enable`
device attributes of the ms_sensors driver shared code.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Link: https://lore.kernel.org/r/20211216185217.1054495-12-lars@metafoo.deSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/common/ms_sensors/ms_sensors_i2c.c

@@ -324,7 +324,7 @@ ssize_t ms_sensors_show_battery_low(struct ms_ht_dev *dev_data,
 	if (ret)
 		return ret;
 
-	return sprintf(buf, "%d\n", (config_reg & 0x40) >> 6);
+	return sysfs_emit(buf, "%d\n", (config_reg & 0x40) >> 6);
 }
 EXPORT_SYMBOL(ms_sensors_show_battery_low);
 
@@ -351,7 +351,7 @@ ssize_t ms_sensors_show_heater(struct ms_ht_dev *dev_data,
 	if (ret)
 		return ret;
 
-	return sprintf(buf, "%d\n", (config_reg & 0x4) >> 2);
+	return sysfs_emit(buf, "%d\n", (config_reg & 0x4) >> 2);
 }
 EXPORT_SYMBOL(ms_sensors_show_heater);