pan/bi: Fix unpack_32_2x16 definition
This got messed up when scalarizing the IR. Fix the definition of the opcode to return (instead of break, asserting out) and to respect the swizzle (instead of failing validation). Noticed when bringing up OpenCL on Valhall.
Fixes: 5febeae5 ("pan/bi: Emit collect and split") Signed-off-by: Alyssa Rosenzweig alyssa@collabora.com