nir/validate: Only require bare types to match for copy_deref

nir/validate: Only require bare types to match for copy_deref

If we want to be able to use copy_deref instructions on explicitly laid
out types, we have to be a little more flexible about what types we
allow.  Instead, of requiring the types to exactly match, only require
the bare types to match.

Reviewed-by: Kristian H. Kristensen <hoegsberg@chromium.org>
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>