ASoC: hide bind/unbind in sysfs

Exposure of driver bind/unbind to userspace via sysfs may
lead to unexpected behavior.
Hide bind and unbind by driver attribute.

Change-Id: I20d6ee653bcc16af15d6368664aaf240c6645cd0
Signed-off-by: Xiaojun Sang <xsang@codeaurora.org>
diff --git a/asoc/codecs/audio-ext-clk-up.c b/asoc/codecs/audio-ext-clk-up.c
index e6e68ad..fcdf5dc 100644
--- a/asoc/codecs/audio-ext-clk-up.c
+++ b/asoc/codecs/audio-ext-clk-up.c
@@ -565,6 +565,7 @@
 		.name = "audio-ref-clk",
 		.owner = THIS_MODULE,
 		.of_match_table = audio_ref_clk_match,
+		.suppress_bind_attrs = true,
 	},
 	.probe = audio_ref_clk_probe,
 	.remove = audio_ref_clk_remove,