r600/sfn: Add the VS in and FS out vectorization

Since the nir default implementation doesn't support vectorizing the VS
inputs and FS outputs, additional lowering passes are added here to do
just that. The work is based on the Timothy Arceri's related work.

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3225>
9 files changed