ASoC: fsl: mpc8610: remove useless assignment

ASoC: fsl: mpc8610: remove useless assignment

cppcheck warning:

sound/soc/fsl/mpc8610_hpcd.c:333:6: style: Redundant initialization
for 'ret'. The initialized value is overwritten before it is
read. [redundantInitialization]
 ret = fsl_asoc_get_dma_channel(np, "fsl,playback-dma",
     ^
sound/soc/fsl/mpc8610_hpcd.c:193:10: note: ret is initialized
 int ret = -ENODEV;
         ^
sound/soc/fsl/mpc8610_hpcd.c:333:6: note: ret is overwritten
 ret = fsl_asoc_get_dma_channel(np, "fsl,playback-dma",
     ^

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20210219232937.6440-9-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>