obs-ffmpeg : use I422 for YUV422P input format

Avoid conversion to UYVY422 for 422P video input files (like dnxhd or xdcam422)
This commit is contained in:
Internal Server Error - Gitea: Git with a cup of tea
500 Internal Server Error

Gitea Version: 1.28.0+dev-477-g8b6ad49a5f