mesa: Remove the key parameter from the _mesa_HashWalk callback

_mesa_HashWalkLocked too.  After the previous couple commits, there are
no users.  This eliminates a lot of unused parameter warnings.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Kristian H. Kristensen <hoegsberg@google.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7171>
14 files changed