save-analysis: Use process_bounds when processing opaque impl item type

...since the code is literally the same and does the same thing.

src/librustc_save_analysis/dump_visitor.rs

@@ -1109,11 +1109,7 @@ fn process_impl_item(&mut self, impl_item: &'l ast::ImplItem, impl_id: DefId) {
                 // FIXME: uses of the assoc type should ideally point to this
                 // 'def' and the name here should be a ref to the def in the
                 // trait.
-                for bound in bounds.iter() {
-                    if let ast::GenericBound::Trait(trait_ref, _) = bound {
-                        self.process_path(trait_ref.trait_ref.ref_id, &trait_ref.trait_ref.path)
-                    }
-                }
+                self.process_bounds(&bounds);
             }
             ast::ImplItemKind::Macro(_) => {}
         }