nir: use the same driver location for packed varyings

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

src/compiler/nir/nir.h

@@ -2312,8 +2312,8 @@ void nir_lower_io_to_temporaries(nir_shader *shader, nir_function *entrypoint,
 
 void nir_shader_gather_info(nir_shader *shader, nir_function_impl *entrypoint);
 
-void nir_assign_var_locations(struct exec_list *var_list,
-                              unsigned *size,
+void nir_assign_var_locations(struct exec_list *var_list, unsigned *size,
+                              unsigned base_offset,
                               int (*type_size)(const struct glsl_type *));
 
 void nir_lower_io(nir_shader *shader,