ASoC: Intel: Fix simultaneous Baytrail SST capture and playback

I managed to drop a change to stream ID setting from commit 49fee178
("ASoC: Intel: Only export one Baytrail DAI") leading to non-working
simultaneous capture-playback since after one DAI conversion
rtd->cpu_dai->id + 1 will be the same for both playback and capture.

Use substream->stream + 1 like it was in original Liam's patch.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Mark Brown <broonie@linaro.org>