ASoC: soc-core: remove duplicate mutex_unlock from snd_soc_unregister_component()

Current snd_soc_unregister_component() is using multiple mutex_unlock()
for found/non-found cases. But it is unreadable and confusable code.
This patch tidyup current code to be readable.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>