panfrost/midgard: Don't force constant on VLUT

Previously, we forced a #0 inline constant tacked on for the lut
instructions to mirror the blob's behaviour, which caused some
suboptimal codegen due to our constant inlining implementation. Instead,
just don't force a constant at all.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Tested-by: Tomeu Vizoso <tomeu.vizoso@collabora.com

src/gallium/drivers/panfrost/midgard/midgard_compile.c

                         .src0 = quirk_flipped_r24 ? SSA_UNUSED_1 : src0,
                         .src1 = quirk_flipped_r24 ? src0         : src1,
                         .dest = dest,
-                        .inline_constant = (nr_inputs == 1) && !quirk_flipped_r24
                 }
         };