avfilter/colorspace: fix dovi peak calculation

[gnattu]

The max PQ to max mastering display luminance calculation is wrong and not within the scale of ffmpeg. This will overflow the pixels during tone mapping unless the user supplies a peak value to overwrite this.

• No need to multiply by reference white for PQ to luminance
• The ffmpeg brightness scale for SMPTE ST.2084 is 100 not 10000

Before: 811943.437500 After: 399.9721366995 (4000 nit master display)

Changes

Issues

[gnattu]

ubuntu noble fails again, not related to this particular PR