radv: add initial non-conformant radv vulkan driver

radv: add initial non-conformant radv vulkan driver

This squashes all the radv development up until now into
one for merging.

History can be found:
https://github.com/airlied/mesa/tree/semi-interesting

This requires llvm 3.9 and is in no way considered
a conformant vulkan implementation. It can run a number
of vulkan applications, and supports all GPUs using
the amdgpu kernel driver.

Thanks to Intel for providing anv and spirv->nir,
and Emil Velikov for reviewing build integration.

Parts of this are:
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Acked-by: Edward O'Callaghan <funfunctor@folklore1984.net>
Authors: Bas Nieuwenhuizen and Dave Airlie
Signed-off-by: Dave Airlie <airlied@redhat.com>