Extend the same reasoning as in the patch listed below. It's not an
error for the workaround list to be empty if no workarounds are needed.
commit 02235808b61cd9382d224b0df263193006dd9913
Author: Francisco Jerez <currojerez@riseup.net>
Date: Wed Oct 7 14:44:01 2015 +0300
drm/i915: Don't warn if the workaround list is empty.