Add feature Cold Redundancy

Add an Intel specific feature PSU Cold Redundancy. This is the first patch
which will get PSU information and PSU Event from D-Bus interfaces.
Cold Redundancy design document is in
https://gerrit.openbmc-project.xyz/c/openbmc/docs/+/27637

Signed-off-by: Cheng C Yang <cheng.c.yang@linux.intel.com>
Change-Id: Ic039118e4cebc8b0ff6ba80493180a1d8af0096b
diff --git a/types.hpp b/types.hpp
index d334a25..814c098 100644
--- a/types.hpp
+++ b/types.hpp
@@ -1,5 +1,5 @@
 #pragma once
-
+#include <array>
 /* const expressions shared in this repository */
 
 constexpr auto ASSOCIATION_IFACE = "xyz.openbmc_project.Association";
@@ -22,3 +22,6 @@
 constexpr auto POWER_OBJ_PATH = "/org/openbmc/control/power0";
 
 constexpr auto INPUT_HISTORY = "input_history";
+
+constexpr std::array<const char*, 1> psuEventInterface = {
+    "xyz.openbmc_project.State.Decorator.OperationalStatus"};