intel/blorp: Plumb the stage through blorp upload_shader

Vulkan uses that for its own upload function -- even though for BLORP
it doesn't really currently care.  Neither Iris and i965 makes use of
it at the moment.

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4170>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4170>
8 files changed