ASoC: madera: Add DT bindings for Cirrus Logic Madera codecs

The Cirrus Logic Madera codecs are a family of related codecs with
extensive digital and analogue I/O, digital mixing and routing,
signal processing and programmable DSPs.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Signed-off-by: Mark Brown <broonie@kernel.org>