ASoC: soc-utils: Remove __exit for snd_soc_util_exit()

snd_soc_util_exit() is called in __init snd_soc_init() for cleanup.
Remove the __exit annotation for it to fix the build warning:

WARNING: modpost: sound/soc/snd-soc-core.o: section mismatch in reference: init_module (section: .init.text) -> snd_soc_util_exit (section: .exit.text)

Fixes: 6ec27c53

 ("ASoC: core: Fix use-after-free in snd_soc_exit()")
Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
Link: https://lore.kernel.org/r/20221031134031.256511-1-chenzhongjin@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>