Add "MMS" to common phone number types.

Partially fixes http://b/2092744
diff --git a/core/java/android/provider/ContactsContract.java b/core/java/android/provider/ContactsContract.java
index afa0a7c..6eaf9dd 100644
--- a/core/java/android/provider/ContactsContract.java
+++ b/core/java/android/provider/ContactsContract.java
@@ -1039,6 +1039,7 @@
             public static final int TYPE_WORK_MOBILE = 17;
             public static final int TYPE_WORK_PAGER = 18;
             public static final int TYPE_ASSISTANT = 19;
+            public static final int TYPE_MMS = 20;
 
             /**
              * The phone number as the user entered it.