avcodec/ljpegenc: Allow full range yuv420p, yuv422p, yuv444p by default

avcodec/ljpegenc: Allow full range yuv420p, yuv422p, yuv444p by default

The documentation for AV_PIX_FMT_YUVJ420P reads:
"planar YUV 4:2:0, 12bpp, full scale (JPEG), deprecated in favor of
AV_PIX_FMT_YUV420P and setting color_range"
Yet the LJPEG encoder only accepts full scale yuv420p when strictness is
set to unofficial or lower; with default strictness it emits a nonsense
error message that says that limit range YUV is unofficial. This has
been changed to allow full range yuv420p, yuv422p and yuv444p irrespective
of the level of strictness.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>