Use correct IntDef in FFmpegAudioDecoder

PiperOrigin-RevId: 389840014

extensions/ffmpeg/src/main/java/com/google/android/exoplayer2/ext/ffmpeg/FfmpegAudioDecoder.java

@@ -41,7 +41,7 @@ import java.util.List;
 
   private final String codecName;
   @Nullable private final byte[] extraData;
-  @C.Encoding private final int encoding;
+  @C.PcmEncoding private final int encoding;
   private final int outputBufferSize;
 
   private long nativeContext; // May be reassigned on resetting the codec.
@@ -158,7 +158,7 @@ import java.util.List;
   }
 
   /** Returns the encoding of output audio. */
-  @C.Encoding
+  @C.PcmEncoding
   public int getEncoding() {
     return encoding;
   }