radv: do not load vertex attributes that are not provided by the pipeline

Per the Vulkan spec this is definitely invalid but X4 Foundations
does that and it ends up by hanging the GPU.

Found while enabling validation layers with the game. The issue
will be reported to the developers.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
(cherry picked from commit 381e38aaaa47c5aa38bc4f504b325fb68b7caea8)