Cycles:
* CUDA: Make it more clear that sm_12 and below is not supported.
* OpenCL: __KERNEL_SHADING__ was declared twice for nvidia opencl device.
* Some reshuffle of defines in kernel_types.h. No functional changes. 

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@53823 954f8c5b-7b00-dc11-b283-0030488c597c