Why do I see a NCSim simulation error when using the Arria 10 Hard IP for PCI Express?

Description

You may see the error below in NCSim when using the Arria® 10 Hard IP for PCI Express®, due to a missing timescale

ncelab: *F,CUMSTS: Timescale directive missing on one or more modules.
ncsim: 13.10-s012: (c) Copyright 1995-2013 Cadence Design Systems, Inc.
ncsim: *F,NOSNAP: Snapshot 'top_tb' does not exist in the libraries.