ASoC: SOF: Intel: hda-dai: fix compilation warning in pcm_prepare

ASoC: SOF: Intel: hda-dai: fix compilation warning in pcm_prepare

Fix GCC warning with W=1, previous cleanup did not remove unnecessary
variable.

sound/soc/sof/intel/hda-dai.c: In function ‘hda_link_pcm_prepare’:

sound/soc/sof/intel/hda-dai.c:265:31: warning: variable ‘hda_stream’
set but not used [-Wunused-but-set-variable]
  265 |  struct sof_intel_hda_stream *hda_stream;
      |                               ^~~~~~~~~~

Fixes: 5098f935424a1 ("ASoC: SOF: Intel: hda: reset link DMA state in prepare")
Cc: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200113205620.27285-1-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>