Add CPER PCIe error section structure and constants definition

On some machine, PCIe error is reported via APEI (ACPI Platform Error
Interface).  The error data is passed from firmware to Linux via CPER
PCIe error section structure.

This patch adds CPER PCIe error section structure and constants
definition.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>