ASoC: SOF: topology: fix: handle DAI widget connections properly with multiple CPU DAI's

Currently, when connecting a DAI widget to the BE CPU DAI, we overwrite
the previous connections. This worked because we only ever had 1 CPU DAI
for each rtd until now. But with multiple CPU DAI's, a new connection
between a BE CPU DAI and the DAI widget should be established without
affecting the previous connections. So, modify the loop to set the
playback/capture widget for the first BE CPU DAI that does not have a
connection established previously.

Fixes: 4a7e26a4d833 ("ASoC: SOF: topology: connect dai widget to all
cpu-dais")

Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Link: https://lore.kernel.org/r/20200415202816.934-2-pierre-louis.bossart@linux.intel.com


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