gallium: add a level parameter to resource parameter get

For lavapipe interface to llvmpipe there is a need to retrieve per-level
info, so this seems like the best interface to use for it.

Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6639>
9 files changed