tu: Don't reference pipeline for some draw states

tu: Don't reference pipeline for some draw states

These draw states are things that depend on pipeline-only state:

- The load state depends on knowing the pipeline layout, which we won't
  know for a shader that's loaded from a binary. This is going away on
  a7xx anyway, and we should be able to use the a7xx strategy of
  prefetching the descriptors in the preamble on a6xx too.
- The prim order state depends on feedback loops and raster order
  attachment access, which isn't supported at the moment.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25276>