st/mesa: stop calling _mesa_init_shader_object_functions()

This sets the LinkShader function for the driver, but for the st we
set it properly with the following call to st_init_program_functions().

Reviewed-by: Marek Olšák <marek.olsak@amd.com>

src/mesa/state_tracker/st_context.c

@@ -714,7 +714,6 @@ void
 st_init_driver_functions(struct pipe_screen *screen,
                          struct dd_function_table *functions)
 {
-   _mesa_init_shader_object_functions(functions);
    _mesa_init_sampler_object_functions(functions);
 
    st_init_draw_functions(functions);