ASoC: soc-compress: Remove unused variable

codec_dai is not used in the function.

sound/soc/soc-compress.c: In function ‘soc_compr_set_params’:
sound/soc/soc-compress.c:156:22: warning:
unused variable ‘codec_dai’ [-Wunused-variable]

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>