net/opal: Fix build with ffmpeg 3.0.x
- Add patch to allow opal to build successfully once multimedia/ffmpeg is updated to 3.0.x. Note that multimedia/ffmpeg is currently still on the 2.8.x branch, however this patch is backwards compatible with ffmpeg 2.8.x.
Reported by: antoine (PR207547)
Approved by: xxx (mentor)
Obtained from: ArchLinux