driconf: add uint64 type

This is needed for panvk, where we want to expose uint64 core masks. The
previous int parsing logic was technically UB rather than guaranteed
truncate-on-overflow, but was likely compiled to truncate in practice.
It is very unlikely that anyone was relying on this.

Signed-off-by: Benjamin Lee <benjamin.lee@collabora.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34374>
3 files changed