ASoC: soc-core: use snd_soc_lookup_component() at snd_soc_unregister_component()

snd_soc_unregister_component() is now finding component manually,
but we already have snd_soc_lookup_component() to find component;
Let's use existing function.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Link: https://lore.kernel.org/r/87zhha252c.wl-kuninori.morimoto.gx@renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>