Update FindCUDA cmake for VS 2017(should works for 2019 since their folder structure is same)

Hi,

When I building the samples of Optix 6.0.0, I found original OptiX FindCUDA cmake didnot find CUDA_HOST_COMPILER correclly.

original post:

  1. https://devtalk.nvidia.com/default/topic/1049059/optix-6-0-0-build-error-with-vs2017-cuda-10-0/
  2. https://github.com/nvpro-samples/optix_advanced_samples/issues/7

And VS project create via cmake-3.14’s FindCUDA cannot correctly compile original sutil tools of OptiX SDK.
(I dont know why…)

so I manually merge the FindCUDA with cmake-3.14’s FindCUDA:
https://github.com/dogod621/FindCUDA_for_OptiX

This version works for me,
and I separate the change in different commit, if you want check the changes.
Please fix the problem~~ thanks~~