ASoC: doc: update codec example code

As the codec API has evolved the documentation has not kept up and still
uses old fields that have been removed.  Update the examples to
represent the current API.

Signed-off-by: John Keeping <john@metanate.com>
Link: https://lore.kernel.org/r/20211024151731.360638-1-john@metanate.com


Signed-off-by: Mark Brown <broonie@kernel.org>