gst/ffmpegcolorspace/gstffmpegcodecmap.c: Replace __VA_ARGS__ caps creation macros...

gst/ffmpegcolorspace/gstffmpegcodecmap.c: Replace __VA_ARGS__ caps creation macros with varargs functions. looks nice...

Original commit message from CVS:
Patch by: Sebastien Moutte  <sebastien moutte net>
* gst/ffmpegcolorspace/gstffmpegcodecmap.c: (gst_ff_vid_caps_new),
(gst_ff_aud_caps_new), (gst_ffmpeg_pixfmt_to_caps),
(gst_ffmpeg_smpfmt_to_caps):
Replace __VA_ARGS__ caps creation macros with varargs functions.
Makes things compile on MSVC (#320765), looks nicer, and we can
tell the compiler to check for the NULL terminator.