ASoC: compare CPU DAI stream name to find BE DAI

While setting up route for a particular device, compare
stream name of CPU DAI and Backend DAI to find the correct
Backend DAI.

Change-Id: Ic3f7c0e5b2a1055e7fdf52c78ded797a9a126d03
Signed-off-by: Banajit Goswami <bgoswami@codeaurora.org>
Signed-off-by: Meng Wang <mwang@codeaurora.org>