Bug#822434: [Stub] update CUDA from 7.5 to 8.0

[lumin]

Hi,

CUDA 8.0 RC version is available for registered users.
https://developer.nvidia.com/cuda-toolkit
I think I shouldn't post the links exposed to registered users
here but I can bring you some information in advance:

* rc version is 8.0.27
* new library nvGRAPH
* clang 3.7 is supported by new NVCC
* GCC-6 support is not mentioned in RC-release note
* likewise CUDA 8.0 is provided for AMD64 and PPC64EL arch, where
  - amd64: .run file and deb files are provided. run file is
    in a size of 1.4GB. deb files are larger. 
  - ppc64el: only deb files for Ubuntu 14.04 and 16.04 are
    provided. size 1.2GB

So we can expect that the CUDA 8.0 bump requires not much change
on the packaging scripts. 

Another thing we need to pay attention to is GCC-6. Stretch freeze
is quarter 1 2017, and I guess CUDA 8.5 release date is around
that point. This means we may need to apply for a freeze-exception
for CUDA package (CUDA 8.5) once CUDA 8.0 fails to work with GCC-6.