ASoC: fsl-sai: don't set bclk for Tx/Rx Synchronous with another SAI mode

In fsl_sai_set_bclk function, we should not set bclk for Tx/Rx Synchronous
with another SAI mode.

Signed-off-by: Zidan Wang <zidan.wang@freescale.com>
Acked-by: Nicolin Chen <nicoleotsuka@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>