pinctrl: cs42l43: Add support for the cs42l43

The CS42L43 is an audio CODEC with integrated MIPI SoundWire interface
(Version 1.2.1 compliant), I2C, SPI, and I2S/TDM interfaces designed
for portable applications. It provides a high dynamic range, stereo
DAC for headphone output, two integrated Class D amplifiers for
loudspeakers, and two ADCs for wired headset microphone input or
stereo line input. PDM inputs are provided for digital microphones.

Add a basic pinctrl driver which supports driver strength for the
various pins, gpios, and pinmux for the 2 multi-function pins.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20230804104602.395892-5-ckeepax@opensource.cirrus.com
Signed-off-by: Lee Jones <lee@kernel.org>