ASoC: soc-core: remove snd_soc_component_add_unlocked()

There is no user to call snd_soc_component_add_unlocked() anymore.
Let's merge snd_soc_component_add_unlocked() and
snd_soc_component_add().

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Reviewed-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>