ASoC: hisilicon: fix spelling mistake: "uknown" -> "unknown"

Trivial fix to spelling mistake in dev_err message text
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

sound/soc/hisilicon/hi6210-i2s.c

@@ -498,7 +498,7 @@ static int hi6210_i2s_trigger(struct snd_pcm_substream *substream, int cmd,
 			hi6210_i2s_txctrl(cpu_dai, 0);
 		break;
 	default:
-		dev_err(cpu_dai->dev, "uknown cmd\n");
+		dev_err(cpu_dai->dev, "unknown cmd\n");
 		return -EINVAL;
 	}
 	return 0;