cinepak: Add another special case so that it can handle the following file:

http://samples.mplayerhq.hu/V-codecs/CVID/bad_cinepak_frame_size.mov



This fix works around another work around which handles a different type
of odd Cinepak data.

Thanks to Matthew Hoops (clone2727 - gmail.com) for the sample and fix.

Signed-off-by: Martin Storsjö <martin@martin.st>