radv/ac/llvm: trim texture return values

radv/ac/llvm: trim texture return values

The intrinsic engine asserts in llvm due to this,
as we put a vec4 into a vec1, and the next instruction
isn't expecting it.

So trim the vector at the end before inserting it.

Reported-by: Christoph Haag <haagch+mesadev@frickel.club>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Cc: "13.0" <mesa-stable@lists.freedesktop.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>