nir: Stop passing an options arg to nir_lower_int64()

nir: Stop passing an options arg to nir_lower_int64()

This information is exposed through shader->options->lower_int64_options.
Removing the extra arg forces drivers to initialize this field correctly.

This also allows us to check the int64 lowering options from each int64
lowering helper and decide if we should lower the instructions we
introduce.

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Rob Clark <robdclark@chromium.org>
Acked-by: Jason Ekstrand <jason@jlekstrand.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5588>