tu: Make sure spirv_to_nir knows we support imageStorageWithoutFormat.

You have to set these flags along with the extension, or you get a bunch
of warnings from spirv-to-nir.

Fixes: e781cc702557 ("tu: Expose shaderStorageImage*WithoutFormat")
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7465>
1 file changed