spirv: Clean up vtn_pointer_to_offset

Now that push constants are using on-the-fly offsets, we no longer need
to handle access chains in vtn_pointer_to_offset.

Acked-by: Rob Clark <robdclark@gmail.com>
Acked-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Acked-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

src/compiler/spirv/vtn_private.h

@@ -679,7 +679,7 @@ nir_deref_instr *vtn_pointer_to_deref(struct vtn_builder *b,
                                       struct vtn_pointer *ptr);
 nir_ssa_def *
 vtn_pointer_to_offset(struct vtn_builder *b, struct vtn_pointer *ptr,
-                      nir_ssa_def **index_out, unsigned *end_idx_out);
+                      nir_ssa_def **index_out);
 
 struct vtn_ssa_value *
 vtn_local_load(struct vtn_builder *b, nir_deref_instr *src);