ASoC: topology: Replace fake root_device with kunit_device in tests

Using struct root_device to create fake devices for tests is something
of a hack. The new struct kunit_device is meant for this purpose, so use
it instead.
Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

sound/soc/soc-topology-test.c

@@ -9,6 +9,7 @@
 #include <sound/core.h>
 #include <sound/soc.h>
 #include <sound/soc-topology.h>
+#include <kunit/device.h>
 #include <kunit/test.h>
 
 /* ===== HELPER FUNCTIONS =================================================== */
@@ -21,26 +22,19 @@
  */
 static struct device *test_dev;
 
-static struct device_driver test_drv = {
-	.name = "sound-soc-topology-test-driver",
-};
-
 static int snd_soc_tplg_test_init(struct kunit *test)
 {
-	test_dev = root_device_register("sound-soc-topology-test");
+	test_dev = kunit_device_register(test, "sound-soc-topology-test");
 	test_dev = get_device(test_dev);
 	if (!test_dev)
 		return -ENODEV;
 
-	test_dev->driver = &test_drv;
-
 	return 0;
 }
 
 static void snd_soc_tplg_test_exit(struct kunit *test)
 {
 	put_device(test_dev);
-	root_device_unregister(test_dev);
 }
 
 /*