SEC checks in IsSevGuest if the PCD defined WorkAreaHeader size
matches the size of the WorkAreaHeader struct definition. Set a
default value for the PCD to avoid unnecessary DSC/FDF file
changes in all OVMF DSC/FDF files.
Signed-off-by: Corvin Köhne <c.koehne@beckhoff.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>