commit fda3bec1 upstream.

This is a 32-bit register. Apparently harmless on real hardware, but
causing justified warnings in simulation.
Signed-off-by: CQ Tang <cq.tang@intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>