ASoC: simple-mux: Depend on gpiolib rather than selecting it

The simple-mux driver requires gpiolib. Currently it selects GPIOLIB but
since the use of select can lead to issues with randconfig let's instead
depend on GPIOLIB, select is more idiomatically used for Kconfig symbols
that are not user selectable but GPIOLIB is user selectable.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220202192333.3655269-7-broonie@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>