iio: inkern: Use max_array() to get the maximum value from an array

Use max_array() to get the maximum value from an array instead of a
custom local loop.
Signed-off-by: Herve Codina <herve.codina@bootlin.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/20230623085830.749991-9-herve.codina@bootlin.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/iio/inkern.c

@@ -5,6 +5,7 @@
  */
 #include <linux/err.h>
 #include <linux/export.h>
+#include <linux/minmax.h>
 #include <linux/mutex.h>
 #include <linux/property.h>
 #include <linux/slab.h>
@@ -875,11 +876,7 @@ static int iio_channel_read_max(struct iio_channel *chan,
 			return -EINVAL;
 		switch (*type) {
 		case IIO_VAL_INT:
-			*val = vals[--length];
-			while (length) {
-				if (vals[--length] > *val)
-					*val = vals[length];
-			}
+			*val = max_array(vals, length);
 			break;
 		default:
 			/* FIXME: learn about max for other iio values */