nir: add indirect loop unrolling to compiler options

nir: add indirect loop unrolling to compiler options

This is where it should be rather than having to pass it into the
optimisation pass every time.

It also allows us to call the loop analysis pass without having to
duplicate these options which we will do later in this series.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12064>