ASoC: Intel: Fix Baytrail IPC double kfree.

struct sst_byt is allocated with devm_kzalloc, but freed on the error
path of sst_byt_dsp_init(). Remove the extra kfree() and fix the error
path.

Signed-off-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>