ASoC: Intel: Atom: platform-pcm: fix redundant return

Fix cppcheck warning

 return ret_val;
        ^
sound/soc/intel/atom/sst-mfld-platform-pcm.c:384:6: note: If condition 'ret_val' is true, the function will return/exit
 if (ret_val)
     ^
sound/soc/intel/atom/sst-mfld-platform-pcm.c:387:9: note: Returning identical expression 'ret_val'
 return ret_val;
        ^

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200813200147.61990-8-pierre-louis.bossart@linux.intel.com


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