Remove unnecessary check when setting permission summary

Activity null check is probably necessary when this logic is written in
fragment, now the logic is in a controller where all dependencies are
self contained, so we don't need to check activity null here.

Change-Id: Ifa32e0d6563c411f19bec07f176765a7c94c8a40
Fixes: 112289663
Test: robotests

src/com/android/settings/applications/appinfo/AppPermissionPreferenceController.java

@@ -46,11 +46,8 @@ public class AppPermissionPreferenceController extends AppInfoPreferenceControll
         public void onPermissionSummaryResult(int standardGrantedPermissionCount,
                 int requestedPermissionCount, int additionalGrantedPermissionCount,
                 List<CharSequence> grantedGroupLabels) {
-            if (mParent.getActivity() == null) {
-                return;
-            }
             final Resources res = mContext.getResources();
-            CharSequence summary = null;
+            CharSequence summary;
 
             if (requestedPermissionCount == 0) {
                 summary = res.getString(