ASoC: max9867: fix type of variable containing error codes

value variable can contain error values and is compared with zero.
Its type must be signed.

The problem has been detected using coccinelle script
scripts/coccinelle/tests/unsigned_lesser_than_zero.cocci
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Reviewed-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/max9867.c

@@ -180,7 +180,8 @@ static int max9867_dai_hw_params(struct snd_pcm_substream *substream,
 {
 	struct snd_soc_codec *codec = dai->codec;
 	struct max9867_priv *max9867 = snd_soc_codec_get_drvdata(codec);
-	unsigned int ni_h, ni_l, value;
+	unsigned int ni_h, ni_l;
+	int value;
 
 	value = get_ni_value(max9867->sysclk, params_rate(params));
 	if (value < 0)