nir/i965/anv/radv/gallium: make shader info a pointer

When restoring something from shader cache we won't have and don't
want to create a nir_shader this change detaches the two.

There are other advantages such as being able to reuse the
shader info populated by GLSL IR.

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>

src/intel/blorp/blorp_clear.c

@@ -56,7 +56,7 @@ blorp_params_get_clear_kernel(struct blorp_context *blorp,
 
    nir_builder b;
    nir_builder_init_simple_shader(&b, NULL, MESA_SHADER_FRAGMENT, NULL);
-   b.shader->info.name = ralloc_strdup(b.shader, "BLORP-clear");
+   b.shader->info->name = ralloc_strdup(b.shader, "BLORP-clear");
 
    nir_variable *v_color = nir_variable_create(b.shader, nir_var_shader_in,
                                                glsl_vec4_type(), "v_color");