pan/mdg: remove ins->alu

This commit removes the `ins->alu` field from midgard_instruction,
simplifying the code by just recreating midgard_vector_alu later when we
have to emit it.

Signed-off-by: Italo Nicola <italonicola@collabora.com>
Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5933>
4 files changed