ASoC: Track which components have been registered with snd_soc_register_component()

snd_soc_unregister_component() takes the parent device of the component as a
parameter and then looks up the component based on this. This is a problem if
multiple components are registered for the same parent device. Currently drivers
do not do this, but some drivers register a CPU DAI component and a platform for
the same parent device. This will become a problem once platforms are also made
components. To make sure that snd_soc_unregister_component() will not
accidentally unregister the platform in such a case only consider components
that were registered with snd_soc_register_component(). This is only meant as
short term stopgap solution to be able to continue componentisation. Long term
we'll need something different.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>