media: make ParameterDescriptor static

Bug: 183242434
Test: builds
Change-Id: Ifed0209d36f6d40b0a9fb95008b74eff5c96c742

core/api/current.txt

@@ -20589,7 +20589,7 @@ package android.media {
     method public long getPresentationTimeUs();
   }
 
-  public class MediaCodec.ParameterDescriptor {
+  public static class MediaCodec.ParameterDescriptor {
     method @NonNull public String getName();
     method public int getType();
   }

media/java/android/media/MediaCodec.java

@@ -4576,7 +4576,7 @@ final public class MediaCodec {
     /**
      * Contains description of a parameter.
      */
-    public class ParameterDescriptor {
+    public static class ParameterDescriptor {
         private ParameterDescriptor() {}
 
         /**