Revert "nir/lower_indirect: Bail early if modes == 0"

    "There's no point in walking the program if we're never going to
    actually lower anything."

Except we might lower compacted local arrays.  In that case, modes will
be 0, but there is still lowering to be done.

This reverts commit 7f75cf2a.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109081


Suggested-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Tested-by: Clayton Craft <clayton.a.craft@intel.com>
Cc: Kenneth Graunke <kenneth@whitecape.org>
(cherry picked from commit 29e4b949)