ACPICA: Tables: Add full support for the DBG2 table.

Updates the DBG2 (Debug Port 2) table definition in the actbl2.h header.

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>