ALSA: hda: cirrus_scodec: Select GPIOLIB for KUnit test

The KUnit test for cirrus_scodec uses GPIO library functions so select
GPIOLIB in Kconfig.

This fixes the ld failures on builds that didn't already select GPIOLIB.
ld: vmlinux.o: in function `cirrus_scodec_test_gpio_get':
sound/pci/hda/cirrus_scodec_test.c:40: undefined reference to
`gpiochip_get_data'
ld: vmlinux.o: in function `cirrus_scodec_test_gpio_probe':
sound/pci/hda/cirrus_scodec_test.c:94: undefined reference to
`gpiochip_generic_request'
ld: sound/pci/hda/cirrus_scodec_test.c:94: undefined reference to
`gpiochip_generic_free'
ld: sound/pci/hda/cirrus_scodec_test.c:95: undefined reference to
`devm_gpiochip_add_data_with_key'

Signed-off-by: Richard Fitzgerald <[e-mail]>
Reported-by: kernel test robot <[e-mail]>
Closes: https://lore.kernel.org/oe-kbuild-all/[e-mail]/
Fixes: 2144833e7b41 ("ALSA: hda: cirrus_scodec: Add KUnit test")
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Takashi Iwai <[e-mail]>

sound/pci/hda/Kconfig

···
 config SND_HDA_CIRRUS_SCODEC_KUNIT_TEST
 	tristate "KUnit test for Cirrus side-codec library" if !KUNIT_ALL_TESTS
 	select SND_HDA_CIRRUS_SCODEC
+	select GPIOLIB
 	depends on KUNIT
 	default KUNIT_ALL_TESTS
 	help