matroskademux: fix handling of MS ACM audio
Pass riff codec-data as strf, not strd, which is where gst_riff_create_audio_caps() expects the WAVEFORMATEXTENSIBLE data.
https://bugzilla.gnome.org/show_bug.cgi?id=757583 Fixes #234 (closed)
Edited by Tim-Philipp Müller