ASoC: cs35l32: Drop legacy include

This driver includes the legacy GPIO API <linux/gpio.h> but
does not use any symbols from it.

Drop the include.

Acked-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20231201-descriptors-sound-cirrus-v2-1-ee9f9d4655eb@linaro.org


Signed-off-by: Mark Brown <broonie@kernel.org>