nir: Silence zillions of unused parameter warnings in release builds

Fixes: cd56d79b "nir: check NIR_SKIP to skip passes by name"
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
(cherry picked from commit 78169870)