FROMLIST: nir/lower_io_to_vector: fix per vertex io handling for arrays

The pass was processing the per vertex index from the wrong end
of the array deref chain.

Fixes: bcd14756eec8 ("nir/lower_io_to_vector: add flat mode")

(am from
https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10798.patch )

BUG=b:177028255
TEST=CtsDeqp on volteer

Change-Id: I86e45318a08fd3f2a3b11465a684c1c33f72fd94
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/mesa/+/2898175
Commit-Queue: Ilja H. Friedel <ihf@chromium.org>
Reviewed-by: Ilja H. Friedel <ihf@chromium.org>
Tested-by: Ilja H. Friedel <ihf@chromium.org>
1 file changed