Fix Proto Generator to not assign types to packages they don't belong to

The wrong type assignment resulted in wrong imports

staging/src/k8s.io/code-generator/cmd/go-to-protobuf/protobuf/namer.go

@@ -116,7 +116,10 @@ func assignGoTypeToProtoPackage(p *protobufPackage, t *types.Type, local, global
 		}
 		return
 	}
-	global[t.Name] = p
+	if t.Name.Package == p.PackagePath {
+		// Associate types only to their own package
+		global[t.Name] = p
+	}
 	if _, ok := local[t.Name]; ok {
 		return
 	}