According to the OptiX denoising guide lines, renders should be in the
0..10000 range. As a result, clamping was applied to renders
prior to GPU denoising.
However this lead to a issue where denoising of bright images would
behave differently between CPU OIDN and GPU OIDN as this same clamping
was also applied to the GPU OIDN denoiser.
According to Attila Áfra, a developer working on OIDN, this clamping
isn't neccesary for OIDN. So this commit removes the clamping from
OIDN.
Pull Request: https://projects.blender.org/blender/blender/pulls/137879