iio: inkern: Replace a FIXME comment by a TODO one

This FIXME comment is more a TODO one.
It is a note when someone will need for this currently unsupported case.

Change from FIXME to TODO.
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Suggested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/20230623085830.749991-10-herve.codina@bootlin.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/iio/inkern.c

@@ -879,7 +879,7 @@ static int iio_channel_read_max(struct iio_channel *chan,
 			*val = max_array(vals, length);
 			break;
 		default:
-			/* FIXME: learn about max for other iio values */
+			/* TODO: learn about max for other iio values */
 			return -EINVAL;
 		}
 		return 0;