cmocka: Fix mixer test before it breaks due to blob handler dependency

Add src/audio/data_blob.c to mixer cmocka test sources to fix the
dependency problem from adding comp_data_blob_handler_new_ext() to
audio/module_adapter/module/generic.c.

Signed-off-by: Jyri Sarha <jyri.sarha@linux.intel.com>

Author: Jyri Sarha

test/cmocka/src/audio/mixer/CMakeLists.txt

@@ -25,6 +25,7 @@ cmocka_test(mixer
 	${PROJECT_SOURCE_DIR}/src/audio/pipeline/pipeline-schedule.c
 	${PROJECT_SOURCE_DIR}/src/audio/pipeline/pipeline-stream.c
 	${PROJECT_SOURCE_DIR}/src/audio/pipeline/pipeline-xrun.c
+	${PROJECT_SOURCE_DIR}/src/audio/data_blob.c
 	${PROJECT_SOURCE_DIR}/src/module/audio/source_api.c
 	${PROJECT_SOURCE_DIR}/src/module/audio/sink_api.c
 	${PROJECT_SOURCE_DIR}/src/math/numbers.c