Static layout: support image verification

Add support of image verification for static layout PNOR code update.

Tested: Verify the PNOR code update succeeds with valid-signed PNOR;
        and fails with invalid-signed PNOR or a PNOR tarball without
        signature.

Change-Id: I1aafeb4e8e07eaa16c170f33f4f21940f7c9c146
Signed-off-by: Lei YU <mine260309@gmail.com>
diff --git a/activation.hpp b/activation.hpp
index 1fcae61..a9fb347 100644
--- a/activation.hpp
+++ b/activation.hpp
@@ -299,12 +299,14 @@
      *        update process in lab environment by checking the
      *        fieldModeEnabled property.
      *
+     * @param[in] pnorFileName - The PNOR filename in image dir
+     *
      * @return  true if successful signature validation or field
      *          mode is disabled.
      *          false for unsuccessful signature validation or
      *          any internal failure during the mapper call.
      */
-    bool validateSignature();
+    bool validateSignature(const std::string& pnorFileName);
 
     /**
      * @brief Gets the fieldModeEnabled property value.