media_kit: Dynamic allocation of ChunkCache based on media

* The "default" of 3MiB wasn't enough for modern larger media
  formats, resulting in inability to play 4k video no matter
  how much horse power you threw at Haiku. (4k is ~8MiB)
* This dynamically calculates the ChunkCache based on the
  video framesize * 2.
* 4k video now plays smoothly on my Ryzen 1800x.

Change-Id: I65bf6bd6fa60ac3196ea70eeeb5e655d43c10bcd
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3598
Reviewed-by: waddlesplash <[email protected]>

headers/private/media/MediaExtractor.h

@@ -79,6 +79,7 @@ private:
 			void				_RecycleLastChunk(stream_info& info);
 	static	int32				_ExtractorEntry(void* arg);
 			void				_ExtractorThread();
+			size_t				_CalculateChunkBuffer(int32 stream);
 
 private:
 			status_t			fInitStatus;