radeonsi: enable R600_DEBUG=nir for vertex and fragment shaders

radeonsi: enable R600_DEBUG=nir for vertex and fragment shaders

Also, disable geometry and tessellation shaders. Mixing and matching NIR
and TGSI shaders should work (and I've tested it for the VS/PS interface),
but geometry and tessellation requires VS-as-ES/LS, which isn't implemented
yet for NIR.

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