ASoC: max98090: Make sure we configure BCLK in one place

BCL is being configured in two places producing a warning message.
Make sure we only configure BCLK once and when we are master.

Signed-off-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Mark Brown <broonie@linaro.org>