Fix launcher preview for two panel follow up

Fixing a possible context issue that was suggested
on the previous CL (ag/15079450) after it got submitted.

Bug: 185508060
Test: manually check launcher preview in wallpaper app
Change-Id: Ia653b833e4c1b911c7d7cac38c35ec2d12ab3a29
diff --git a/src/com/android/launcher3/graphics/PreviewSurfaceRenderer.java b/src/com/android/launcher3/graphics/PreviewSurfaceRenderer.java
index f3087c0..d0464a4 100644
--- a/src/com/android/launcher3/graphics/PreviewSurfaceRenderer.java
+++ b/src/com/android/launcher3/graphics/PreviewSurfaceRenderer.java
@@ -165,7 +165,7 @@
 
                 @Override
                 public void run() {
-                    DeviceProfile deviceProfile = mIdp.getDeviceProfile(mContext);
+                    DeviceProfile deviceProfile = mIdp.getDeviceProfile(previewContext);
                     String query = (deviceProfile.isTwoPanels ? LauncherSettings.Favorites.SCREEN
                             + " = " + Workspace.LEFT_PANEL_ID + " or " : "")
                             + LauncherSettings.Favorites.SCREEN + " = " + Workspace.FIRST_SCREEN_ID