[media] add the sbc and aptx encodings to fuchsia.media

The FIDL library fuchsia.media was missing constant definitions for
the SBC and APTX audio encodings. This CL adds them.

TEST: no behavior change

Change-Id: Iba61d0b3ad7a59733064c73de4bb7452066bb6bd
diff --git a/public/fidl/fuchsia.media/stream_type.fidl b/public/fidl/fuchsia.media/stream_type.fidl
index ad8a6fc..e37e010 100644
--- a/public/fidl/fuchsia.media/stream_type.fidl
+++ b/public/fidl/fuchsia.media/stream_type.fidl
@@ -29,12 +29,14 @@
 const string AUDIO_ENCODING_AAC = "fuchsia.media.aac";
 const string AUDIO_ENCODING_AMRNB = "fuchsia.media.amrnb";
 const string AUDIO_ENCODING_AMRWB = "fuchsia.media.amrwb";
+const string AUDIO_ENCODING_APTX = "fuchsia.media.aptx";
 const string AUDIO_ENCODING_FLAC = "fuchsia.media.flac";
 const string AUDIO_ENCODING_GSMMS = "fuchsia.media.gsmms";
 const string AUDIO_ENCODING_LPCM = "fuchsia.media.lpcm";
 const string AUDIO_ENCODING_MP3 = "fuchsia.media.mp3";
 const string AUDIO_ENCODING_PCMALAW = "fuchsia.media.pcmalaw";
 const string AUDIO_ENCODING_PCMMULAW = "fuchsia.media.pcmmulaw";
+const string AUDIO_ENCODING_SBC = "fuchsia.media.sbc";
 const string AUDIO_ENCODING_VORBIS = "fuchsia.media.vorbis";
 
 const string VIDEO_ENCODING_H263 = "fuchsia.media.h263";