ASoC: fsl_ssi: AC'97 DAI driver needs probe method too

AC'97 DAI driver struct need the same probe method as
I2S one to setup DMA params in fsl_ssi driver.

Signed-off-by: Maciej Szmigiero <mail@maciej.szmigiero.name>
Signed-off-by: Mark Brown <broonie@kernel.org>