nir/deref: Add a has_complex_use helper

This lets passes easily detect derefs which have uses that fall outside
the standard load/store/copy pattern so they can bail appropriately.

Reviewed-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>

src/compiler/nir/nir.h

@@ -1085,6 +1085,7 @@ nir_deref_instr_get_variable(const nir_deref_instr *instr)
 }
 
 bool nir_deref_instr_has_indirect(nir_deref_instr *instr);
+bool nir_deref_instr_has_complex_use(nir_deref_instr *instr);
 
 bool nir_deref_instr_remove_if_unused(nir_deref_instr *instr);