bespillutil: Remove redundant check.

The same check is just a few lines above.

ir/be/bespillutil.c

@@ -784,12 +784,10 @@ static void prepare_constr_insn(ir_node *const node)
 		} else {
 			if (def_constr == NULL || req->limited == NULL)
 				continue;
-			if (!req->kills_value) {
 			const arch_register_req_t *const in_req
 				= arch_get_irn_register_req(in);
 			if (in_req->ignore)
 				continue;
-			}
 
 			bool                               common_limits = false;
 			arch_register_class_t const *const cls           = req->cls;