Fixing long-press in syste-drag does not initialize the event pos

Bug: 147899070
Change-Id: I73bc7d5addde5fb3304cac29f0ecce17b2cc48ea
diff --git a/src/com/android/launcher3/dragndrop/DragController.java b/src/com/android/launcher3/dragndrop/DragController.java
index 1b7b015..de7bc6d 100644
--- a/src/com/android/launcher3/dragndrop/DragController.java
+++ b/src/com/android/launcher3/dragndrop/DragController.java
@@ -160,8 +160,8 @@
 
         mOptions = options;
         if (mOptions.systemDndStartPoint != null) {
-            mMotionDownX = mOptions.systemDndStartPoint.x;
-            mMotionDownY = mOptions.systemDndStartPoint.y;
+            mLastTouch[0] = mMotionDownX = mOptions.systemDndStartPoint.x;
+            mLastTouch[1] = mMotionDownY = mOptions.systemDndStartPoint.y;
         }
 
         final int registrationX = mMotionDownX - dragLayerX;