ASoC: SOF: Intel: hda-codec: move variable used conditionally

Cppcheck reports the following warning:

sound/soc/sof/intel/hda-codec.c:122:20: style: Unused variable: codec
[unusedVariable]
 struct hda_codec *codec;
                   ^

Move declaration inside a conditionally-compiled block.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200813175839.59422-3-pierre-louis.bossart@linux.intel.com


Signed-off-by: Mark Brown <broonie@kernel.org>