Removed useless function Type::ref.

Test: make hidl-gen, hidl_test
Change-Id: I9358a12d43b2a856e5150eb69fb8bc9ccfadf65b
diff --git a/AST.cpp b/AST.cpp
index a1fab37..016204b 100644
--- a/AST.cpp
+++ b/AST.cpp
@@ -227,7 +227,7 @@
                     type = static_cast<TypeDef *>(type)->referencedType();
                 }
 
-                return type->ref();
+                return type;
             }
         }
     }
@@ -347,7 +347,7 @@
         }
     }
 
-    return returnedType->ref();
+    return returnedType;
 }
 
 Type *AST::findDefinedType(const FQName &fqName, FQName *matchingName) const {