Revert "audio/audio_pt_int: Clarify licensing"

This reverts commit 72bc6f1bf710e205f175af9b1fc8bbd83e8da71f.

This patch wasn't submitted to the list and did not get Acked by other
copyright holders in the file.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/audio/audio_pt_int.c b/audio/audio_pt_int.c
index e3ccb11..9a9c306 100644
--- a/audio/audio_pt_int.c
+++ b/audio/audio_pt_int.c
@@ -1,4 +1,3 @@
-/* public domain */
 #include "qemu-common.h"
 #include "audio.h"