Static layout: Implement PNOR code update

Implement the PNOR code update by pflash tool in openpower-pnor-update
service, and update the related associations.

Tested: Verify PNOR code update succeeds.

Change-Id: I53781d6420071200ac2ed6837f7a79bf5e1162c2
Signed-off-by: Lei YU <mine260309@gmail.com>
diff --git a/static/activation_static.hpp b/static/activation_static.hpp
index 85914ac..6fe7138 100644
--- a/static/activation_static.hpp
+++ b/static/activation_static.hpp
@@ -17,11 +17,14 @@
   public:
     using Activation::Activation;
     ~ActivationStatic() = default;
+    Activations activation(Activations value) override;
 
   private:
     void unitStateChange(sdbusplus::message::message& msg) override;
     void startActivation() override;
     void finishActivation() override;
+
+    std::string pnorUpdateUnit;
 };
 
 } // namespace updater