Try to depend only on the ir module being in scope.

Generated code should used qualified names assuming that `ir` is in
scope, not everything else.

lib/cretonne/src/isa/intel/enc_tables.rs

@@ -1,6 +1,6 @@
 //! Encoding tables for Intel ISAs.
 
-use ir::{self, types, Opcode};
+use ir;
 use isa;
 use isa::constraints::*;
 use isa::enc_tables::*;