ASoC: sh: dma-sh7760: remove unused variable

cppcheck warning:

sound/soc/sh/dma-sh7760.c:180:6: style: Unused variable: ret
[unusedVariable]
 int ret;
     ^

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20210219231635.5749-2-pierre-louis.bossart@linux.intel.com


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