anv: Add pipeline_has_stage guards a few places

All of these worked before because they were depending on prog_data to be
null.  Soon, we won't be able to depend on a nice prog_data pointer and
it's nice to be more explicit anyway.

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Cc: "12.0" <mesa-stable@lists.freedesktop.org>

src/intel/vulkan/anv_private.h

@@ -1520,6 +1520,13 @@ struct anv_pipeline {
    } gen9;
 };
 
+static inline bool
+anv_pipeline_has_stage(const struct anv_pipeline *pipeline,
+                       gl_shader_stage stage)
+{
+   return (pipeline->active_stages & mesa_to_vk_shader_stage(stage)) != 0;
+}
+
 static inline const struct brw_vs_prog_data *
 get_vs_prog_data(struct anv_pipeline *pipeline)
 {