cmd/mbf: do not open cache for IR encoding

This can now be allocated independently.

Signed-off-by: Ophestra <cat@gensokyo.uk>

cmd/mbf/main.go

@@ -433,9 +433,7 @@ func main() {
 						return err
 					}
 
-					if err = cm.Do(func(cache *pkg.Cache) error {
-						return cache.EncodeAll(f, rosa.Std.Load(p))
-					}); err != nil {
+					if err = pkg.NewIR().EncodeAll(f, rosa.Std.Load(p)); err != nil {
 						_ = f.Close()
 						return err
 					}