Make sure the ringer drawer is present before trying to hide it.

Fixes: 181751039
Test: I don't have a TV device, but it's just a null check
Change-Id: Ic26a81e1bec67106b7b6154438bac0cabc07dc60

packages/SystemUI/src/com/android/systemui/volume/VolumeDialogImpl.java

@@ -778,6 +778,12 @@ public class VolumeDialogImpl implements VolumeDialog,
 
     /** Animates away the ringer drawer. */
     private void hideRingerDrawer() {
+
+        // If the ringer drawer isn't present, don't try to hide it.
+        if (mRingerDrawerContainer == null) {
+            return;
+        }
+
         // Hide the drawer icon for the selected ringer - it's visible in the ringer button and we
         // don't want to be able to see it while it animates away.
         getDrawerIconViewForMode(mState.ringerModeInternal).setVisibility(INVISIBLE);