ASoC: bt-sco: Add generic compatible string

Provide a common compatible string for device trees to list as a fallback
for simplicity. We don't currently have a binding document but let's not
fix that right now...

Signed-off-by: Mark Brown <broonie@linaro.org>
diff --git a/sound/soc/codecs/bt-sco.c b/sound/soc/codecs/bt-sco.c
index a081d9f..5c040ce 100644
--- a/sound/soc/codecs/bt-sco.c
+++ b/sound/soc/codecs/bt-sco.c
@@ -50,6 +50,9 @@
 	{
 		.name		= "dfbmcs320",
 	},
+	{
+		.name		= "bt-sco",
+	},
 	{},
 };
 MODULE_DEVICE_TABLE(platform, bt_sco_driver_ids);