ASoC: tegra_rt5640: Correct a copy and paste typo in the comments

This patch corrects a copy and paste typo.
Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/tegra/tegra_rt5640.c

 /*
-* tegra_rt5640.c - Tegra machine ASoC driver for boards using WM8903 codec.
+* tegra_rt5640.c - Tegra machine ASoC driver for boards using RT5640 codec.
  *
  * Copyright (c) 2013, NVIDIA CORPORATION.  All rights reserved.
  *