avcodec: remove libutvideo wrapper support

The 10-bit decoding support is available now in native decoder.

Signed-off-by: Paul B Mahol <onemda@gmail.com>

LICENSE.md

@@ -17,7 +17,6 @@ Specifically, the GPL parts of FFmpeg are:
     - `libavcodec/x86/flac_dsp_gpl.asm`
     - `libavcodec/x86/idct_mmx.c`
     - `libavfilter/x86/vf_removegrain.asm`
-- libutvideo encoding/decoding wrappers in `libavcodec/libutvideo*.cpp`
 - the X11 grabber in `libavdevice/x11grab.c`
 - the following building and testing tools
     - `compat/solaris/make_sunver.pl`
@@ -87,7 +86,6 @@ The following libraries are under GPL:
 - frei0r
 - libcdio
 - librubberband
-- libutvideo
 - libvidstab
 - libx264
 - libx265