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/ubi/activation_ubi.cpp b/ubi/activation_ubi.cpp
index 9ce7085..5c57c4b 100644
--- a/ubi/activation_ubi.cpp
+++ b/ubi/activation_ubi.cpp
@@ -40,7 +40,7 @@
 
 #ifdef WANT_SIGNATURE_VERIFY
             // Validate the signed image.
-            if (!validateSignature())
+            if (!validateSignature(squashFSImage))
             {
                 // Cleanup
                 activationBlocksTransition.reset(nullptr);
diff --git a/ubi/activation_ubi.hpp b/ubi/activation_ubi.hpp
index c0ffa01..a6ef436 100644
--- a/ubi/activation_ubi.hpp
+++ b/ubi/activation_ubi.hpp
@@ -9,6 +9,8 @@
 namespace updater
 {
 
+constexpr auto squashFSImage = "pnor.xz.squashfs";
+
 class RedundancyPriorityUbi : public RedundancyPriority
 {
   public:
diff --git a/ubi/item_updater_ubi.cpp b/ubi/item_updater_ubi.cpp
index 188b0bf..227bc1a 100644
--- a/ubi/item_updater_ubi.cpp
+++ b/ubi/item_updater_ubi.cpp
@@ -30,8 +30,6 @@
 using namespace sdbusplus::xyz::openbmc_project::Common::Error;
 using namespace phosphor::logging;
 
-constexpr auto squashFSImage = "pnor.xz.squashfs";
-
 std::unique_ptr<Activation> ItemUpdaterUbi::createActivationObject(
     const std::string& path, const std::string& versionId,
     const std::string& extVersion,