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

sound/soc/Kconfig

@@ -38,6 +38,17 @@ config SND_SOC_TOPOLOGY
 	bool
 	select SND_DYNAMIC_MINORS
 
+config SND_SOC_TOPOLOGY_BUILD
+	bool "Build topology core"
+	select SND_SOC_TOPOLOGY
+	depends on KUNIT
+	help
+	  This option exists to facilitate running the KUnit tests for
+	  the topology core, KUnit is frequently tested in virtual
+	  environments with minimal drivers enabled but the topology
+	  core is usually selected by drivers.  There is little reason
+	  to enable it if not doing a KUnit build.
+
 config SND_SOC_TOPOLOGY_KUNIT_TEST
 	tristate "KUnit tests for SoC topology"
 	depends on KUNIT

tools/testing/kunit/configs/all_tests.config

@@ -39,3 +39,4 @@ CONFIG_SECURITY_APPARMOR=y
 CONFIG_SOUND=y
 CONFIG_SND=y
 CONFIG_SND_SOC=y
+CONFIG_SND_SOC_TOPOLOGY_BUILD=y