Remove reference to preference_category_material_settings

This layout in settingslib has been migrated to the support library's
preference_category_material, so we can just reference that.

Bug: 110037570
Test: manual (format of category headers should look normal in Settings
timezone picker)

Change-Id: I32df326e1d4afd4d7ae6f694c38554f3d0f54e84

src/com/android/settings/datetime/timezone/BaseTimeZoneAdapter.java

@@ -78,7 +78,7 @@ public class BaseTimeZoneAdapter<T extends BaseTimeZoneAdapter.AdapterItem>
         LayoutInflater inflater = LayoutInflater.from(parent.getContext());
         switch(viewType) {
             case TYPE_HEADER: {
-                final View view = inflater.inflate(R.layout.preference_category_material_settings,
+                final View view = inflater.inflate(R.layout.preference_category_material,
                         parent, false);
                 return new HeaderViewHolder(view);
             }