ASoC: fsl_sai: Cleanups and 1:1 bclk:mclk ratio support

Merge series from Sascha Hauer <s.hauer@pengutronix.de>:

This series has some updates for the fsl_sai driver: Some general
cleanup patches, a bugfix in the ip revision checking and finally
the mclk setting is made more accurate and support for 1:1 bclk:mclk
setting is added.