radeonsi: don't scalarize 16-bit vec2 ALU opcodes

prerequisite for enabling vectorization, so that we don't scalarize
and vectorize at the same time, causing an infinite loop.

Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6622>
1 file changed