Fixes a regression due to the fact that the colorspace filter does
not use the new API introduced by 8c7934f7.
The scale filter uses it since 45e09a30, and the setparams
filter since 3bf80df3.

Example:
ffprobe -f lavfi yuvtestsrc,setparams=color_primaries=bt470bg:color_trc=
bt470bg:colorspace=bt470bg,colorspace=bt709:range=tv,scale,showinfo

Before:
  color_range:unknown color_space:bt470bg ...
After:
  color_range:tv color_space:bt709 ...
Signed-off-by: Nicolas Gaullier <nicolas.gaullier@cji.paris>
Signed-off-by: Niklas Haas <git@haasn.dev>