ASoC: topology: Add explicit build option

The default KUnit build options are not supposed to enable any
subsystems that were not already enabled but the topology code is a
library which is generally selected by drivers that want to use it.
Since KUnit is frequently run in virtual environments with minimal
driver support this makes it difficult to enable the toplogy tests so
provide an explicit Kconfig option which can be directly enabled when
using KUnit, and also include this in the KUnit all_tests.config.

Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230718-asoc-topology-kunit-enable-v2-5-0ee11e662b92@kernel.org


Signed-off-by: Mark Brown <broonie@kernel.org>