We already have dummy-codec, dummy-platform.
But its issues are
	1) we don't have dummy-cpu,
	2) we can't select it via DeviceTree
	3) It do nothing

Sometimes we want to have Dummy Sound Component for debugging,
for testing, for learning Framework behavior, etc, etc...
This patch adds Test-Component driver for it.

User can select CPU   Component by using "test-cpu"   compatible,
and  can select Codec Component by using "test-codec" compatible.

It doesn't support Platform so far, but is easy to add.

We can verbose print to know its progress if user selected
xxx-verbose compatible driver.

for example,
	test-cpu		   : silent  Component, silent  DAI
	test-cpu-verbose-component : verbose Component, silent  DAI
	test-cpu-verbose-dai	   : silent  Component, verbose DAI
	test-cpu-verbose	   : verbose Component, verbose DAI
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/877dein8rx.wl-kuninori.morimoto.gx@renesas.comSigned-off-by: Mark Brown <broonie@kernel.org>