radv: Set driver version to mesa version;

radv: Set driver version to mesa version;

I couldn't really find an encoding in the spec. I'm not sure it
prescribes VK_MAKE_VERSION format, but vulkan.gpuinfo.org interprets
it that way by default. vulkaninfo gives the raw number, so we could
alternatively do something like 17001000, but that doesn't show
up right on vulkan.gpuinfo.org again. Looking at that site, the -pro
driver also uses VK_MAKE_VERSION, so keeping consistency is probably
best.

Signed-off-by: Bas Nieuwenhuizen <basni@google.com>
Acked-by: Dave Airlie <airlied@redhat.com>