Make getter & setting names consistent.

Test: runtest systemui-notification
Change-Id: Iff746f0ae149d1b09792e240503db9d008fe267c
diff --git a/core/java/android/app/Notification.java b/core/java/android/app/Notification.java
index bdb2685..261fde2 100644
--- a/core/java/android/app/Notification.java
+++ b/core/java/android/app/Notification.java
@@ -2239,7 +2239,7 @@
     /**
      * Returns the id of the channel this notification posts to.
      */
-    public String getNotificationChannel() {
+    public String getChannel() {
         return mChannelId;
     }