venus/pipeline: Refactor vn_fix_graphics_pipeline_create_info

venus/pipeline: Refactor vn_fix_graphics_pipeline_create_info

- Instead of deferring all fixes until we inspect all pCreateInfos, fix
  each pCreateInfo immediately after we inspect it.
- Do not allocate vn_graphics_pipeline_create_info_fix.
- Add a struct to hold the temporary allocation of fixed pCreateInfos.
  Later commits will place more vk structs here.

Signed-off-by: Chad Versace <chadversary@chromium.org>
Reviewed-by: Yiwei Zhang <zzyiwei@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16681>