Staging: iio: fix up the iio_get_new_idr_val comment

improve the comment a bit

Cc: Greg KH <greg@kroah.com>
Cc: Jonathan Cameron <jic23@cam.ac.uk>
Cc: Sonic Zhang <sonic.adi@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/iio/industrialio-core.c

@@ -537,7 +537,7 @@ static void iio_device_unregister_sysfs(struct iio_dev *dev_info)
 	sysfs_remove_group(&dev_info->dev.kobj, dev_info->attrs);
 }
 
-/* This function return negative value if fails. */
+/* Return a negative errno on failure */
 int iio_get_new_idr_val(struct idr *this_idr)
 {
 	int ret;