Fix missing VM mapping

When processing FORWARD records, we weren't accounting for the pointer
being in the physical address space and not the virtual space instead.

Change-Id: I35ef637fbec7886d4cfeac5fd650a17eae8d555a
Signed-off-by: Philip Prindeville <philipp@redfish-solutions.com>
Reviewed-on: http://review.coreboot.org/499
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>