iio/adjd_s311: Fix potential memory leak in adjd_s311_update_scan_mode()

Do not leak memory by updating pointer with potentially NULL realloc return value.
There is no need to preserve data in the buffer,
so replace krealloc() by kfree()-kmalloc() pair.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Acked-by: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/drivers/iio/light/adjd_s311.c b/drivers/iio/light/adjd_s311.c
index 1cbb449..9a99f43 100644
--- a/drivers/iio/light/adjd_s311.c
+++ b/drivers/iio/light/adjd_s311.c
@@ -271,9 +271,10 @@
 	const unsigned long *scan_mask)
 {
 	struct adjd_s311_data *data = iio_priv(indio_dev);
-	data->buffer = krealloc(data->buffer, indio_dev->scan_bytes,
-				GFP_KERNEL);
-	if (!data->buffer)
+
+	kfree(data->buffer);
+	data->buffer = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
+	if (data->buffer == NULL)
 		return -ENOMEM;
 
 	return 0;