Ignore lint error RtlHardcoded for AwZoomControls

The following lint error is reported while building
android_webview_apk can be ignored:

AwZoomControls.java:76 Use "`Gravity.END`" instead of "`Gravity.RIGHT`"
to ensure correct behavior in right-to-left locales: RtlHardcoded [warning]
((FrameLayout.LayoutParams) params).gravity = Gravity.RIGHT;

BUG=None.

Review URL: https://codereview.chromium.org/1013713003

Cr-Commit-Position: refs/heads/master@{#320864}

android_webview/java/src/org/chromium/android_webview/AwZoomControls.java

@@ -4,6 +4,7 @@
 
 package org.chromium.android_webview;
 
+import android.annotation.SuppressLint;
 import android.view.Gravity;
 import android.view.View;
 import android.view.ViewGroup;
@@ -61,6 +62,7 @@ class AwZoomControls implements ZoomControlsDelegate {
         return mZoomButtonsController != null ? mZoomButtonsController.getZoomControls() : null;
     }
 
+    @SuppressLint("RtlHardcoded")
     private ZoomButtonsController getZoomController() {
         if (mZoomButtonsController == null
                 && mAwContents.getSettings().shouldDisplayZoomControls()) {