radv: fix NGG streamout when it's never enabled in runtime

radv: fix NGG streamout when it's never enabled in runtime

If a shader has XFB outputs but the application never enables
streamout in runtime (no buffers bound and no begin/end pair), we
have to disable it in the shader by emitting buffer size as 0. It's
also still needed to remember that the cmdbuf needs GDS/GDS OA BOs,
so move this at pipeline bind time instead.

Cc: 22.3 mesa-stable
Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/19801>
(cherry picked from commit 3189be249d4489f7943da6c90ee521bde8624041)