multimedia/ffmpeg: unbreak SVTHEVC=on after 685e477b807c

> Applying distribution patches for ffmpeg-6.0,1

3 out of 4 hunks failed--saving rejects to configure.rej
1 out of 1 hunks failed--saving rejects to libavcodec/allcodecs.c.rej

> FAILED Applying distribution patch 0001-lavc-svt_hevc-add-libsvt-hevc-encoder-wrapper.patch with -p1

PR: 261302
Reported by: VVD