Revert "intel/nir: Call nir_lower_io_to_scalar_early"

Commit 4434591b caused substantially more URB messages in
geometry and tessellation shaders.  Before we can really enable this
sort of optimization,  We either need some way of combining them back
together into vectors or we need to do cross-stage vector element
elimination without splitting everything into scalars.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107510


Fixes: 4434591b "intel/nir: Call nir_lower_io_to_scalar_early"
Acked-by: Kenneth Graunke <kenneth@whitecape.org>
Tested-by: Mark Janes <mark.a.janes@intel.com>
(cherry picked from commit 10f44da7)