Blender Git Loki

Fix CUDA out of memory error with OptiX viewport denoising on small GPUs

This makes the memory allocation for the denoiser state use the memory allocator in Cycles, which
will evict textures to host memory when there is not enough space on the device. This means the
allocation for the denoiser state won't just fail if there is no more space and instead more space is
made for it to work. Also simplifies code somewhat.