Add "mclk" support for maxim,max9867

Merge series from richard.leitner@linux.dev:

This series adds support for the clocks properties in the
maxim,max9867 bindings. Furthermore the binding definitions are
converted from txt to yaml.

The clock property is needed to define the mclk for one of our
boards which uses the the i.MX8MP SAI MCLK as clock for the
maxim,max9867.