Blender Git Loki

Fix Cycles rendering with OptiX after instance limit increase when building with old SDK

Commit d259e7dcfbbd37cec5a45fdfb554f24de10d0268 increased the instance limit, but only provided
a fall back for the host code for older OptiX SDKs, not for kernel code. This caused a mismatch when
an old SDK was used (as is currently the case on buildbot) and subsequent rendering artifacts. This
fixes that by moving the bit that is checked to a common location that works with both old an new
SDK versions.