ASoC: cs4271: free allocated GPIO

In case of probe deferral, the allocated GPIO line is not freed, which
prevents it from being claimed and properly asserted in later attempts.

Fix this by using devm_gpio_request().

Signed-off-by: Daniel Mack <zonque@gmail.com>
Reported-by: Michael Hirsch <hirsch@teufel.de>
Cc: Alexander Sverdlin <subaparts@yandex.ru>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>