If the DT is used and the CPU DAI device has only one DAI, the card
name will be like :

ALSA device list:
0: 40031000.sai-sgtl5000

And this name maybe a little ugly to some customers, so here the
card name parsing from DT node is supported.
Signed-off-by: NXiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: NMark Brown <broonie@linaro.org>