Change some big functions from __device_inline to __device, which
makes CPU kernel compilation much faster when using MSVC.

Sideeffect of this change is that CPU rendering is few percent
faster now. CUDA rendering is the same speed.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@53791 954f8c5b-7b00-dc11-b283-0030488c597c