Fixed warning on incompatible pointer types

Signed-off-by: Felix Paul Kühne <fkuehne@videolan.org>
contrib: fix compilation of libraries for iOS which deploy cmake
demux: asf: remember extended stream parameters for tracks
demux: asf: fix keyframe waiting after a seek (fix #6647)

Having pts doesn't mean we have a valid index.
Also, waiting 50 frames, including all streams is pointless.
We expect at least a keyframe within 60 sec on seek track.
This wait is lowered to 5 sec of data if we estimate a low
bandwidth (that one might need a better hint)