spirv: Add support for using derefs for UBO/SSBO access

For now, it's hidden behind a cap.  Hopefully, we can eventually drop
that along with all the manual offset code in spirv_to_nir.

Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Tested-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>

src/amd/vulkan/radv_shader.c

@@ -219,6 +219,7 @@ radv_shader_compile_to_nir(struct radv_device *device,
 			}
 		}
 		const struct spirv_to_nir_options spirv_options = {
+			.lower_ubo_ssbo_access_to_offsets = true,
 			.caps = {
 				.device_group = true,
 				.draw_parameters = true,