zink: zink: add parent to zink_shader::non_fs

For a generated gs this field will store a pointer to the shader that
"owns" it.

Reviewed-by: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Reviewed-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21238>

src/gallium/drivers/zink/zink_program.c

@@ -2330,6 +2330,7 @@ zink_set_primitive_emulation_keys(struct zink_context *ctx)
             shader->needs_inlining = true;
             ctx->gfx_stages[prev_vertex_stage]->non_fs.generated_gs[ctx->gfx_pipeline_state.gfx_prim_mode][zink_prim_type] = shader;
             shader->non_fs.is_generated = true;
+            shader->non_fs.parent = ctx->gfx_stages[prev_vertex_stage];
             shader->can_inline = true;
             shader->sinfo.so_info = ctx->gfx_stages[prev_vertex_stage]->sinfo.so_info;
          }

src/gallium/drivers/zink/zink_types.h

@@ -768,6 +768,8 @@ struct zink_shader {
       struct {
          struct zink_shader *generated_tcs; // a generated shader that this shader "owns"; only valid in the tes stage
          struct zink_shader *generated_gs[PIPE_PRIM_MAX][ZINK_PRIM_MAX]; // generated shaders that this shader "owns"
+         struct zink_shader *parent; // for a generated gs this points to the shader that "owns" it
+
          bool is_generated; // if this is a driver-created shader (e.g., tcs)
       } non_fs;