ASoC: fsl-asoc-card: use different route map for AC'97 mode

fsl_ssi uses different stream names ("AC97 Playback" / "AC97 Capture")
in AC'97 mode so in this case fsl-asoc-card route map should
also be using them.

Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
Acked-by: Nicolin Chen <nicoleotsuka@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>