pinctrl: madera: Add configuration for Cirrus Logic CS47L15

This adds the pinctrl configuration for the CS47L15 codec to
the madera pinctrl driver.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20190722091015.20884-2-ckeepax@opensource.cirrus.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>