meson: disable some more warnings on msvc

These warnings triggers for me, and they are harmless as-is. Let's
disable them to avoid hiding actually scary warnings.

Reviewed-by: Jose Fonseca <jfonseca@vmware.com>
Reviewed-by: Charmaine Lee <charmainel@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4343>
1 file changed