regulator: arizona-micsupp: Add support for Cirrus Logic Madera codecs

This adds a new driver identity "madera-micsupp" and probe function
so that this driver can be used to control the micsupp regulator on
Cirrus Logic Madera codecs.

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>