Fix Java 7 build.

See http://bugs.sun.com/view_bug.do?bug_id=6904536
Bug: 8992787

Change-Id: Ib84a28a3df4517be86cd3342e6f916a5d905be89
diff --git a/libart/src/main/java/java/lang/Enum.java b/libart/src/main/java/java/lang/Enum.java
index f98554a..43ac113 100644
--- a/libart/src/main/java/java/lang/Enum.java
+++ b/libart/src/main/java/java/lang/Enum.java
@@ -148,7 +148,7 @@
      * @see java.lang.Comparable
      */
     public final int compareTo(E o) {
-        return ordinal - o.ordinal;
+        return ordinal - o.ordinal();
     }
 
     /**
diff --git a/libdvm/src/main/java/java/lang/Enum.java b/libdvm/src/main/java/java/lang/Enum.java
index 7a0f514..4b897aa 100644
--- a/libdvm/src/main/java/java/lang/Enum.java
+++ b/libdvm/src/main/java/java/lang/Enum.java
@@ -147,7 +147,7 @@
      * @see java.lang.Comparable
      */
     public final int compareTo(E o) {
-        return ordinal - o.ordinal;
+        return ordinal - o.ordinal();
     }
 
     /**