ASoC: madera: Update SPDX headers

The madera driver was merged too late to catch Thomas Gleixner's cleanup
of the SPDX headers tree wide. Update the headers to match what was done
in that patch.

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

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>