Revert "Remove single FAB functionality"

This reverts commit e8dfecd57258c51cda7ccd5e6dbbc594c877b8c1.

Change-Id: Ic3478d568450180b06958d480d2c621416de0247
Signed-off-by: Jinu Joy Thomas <jinu.joy.thomas@in.ibm.com>
diff --git a/vpd-manager/src/manager.cpp b/vpd-manager/src/manager.cpp
index db89920..37fe02b 100644
--- a/vpd-manager/src/manager.cpp
+++ b/vpd-manager/src/manager.cpp
@@ -27,8 +27,7 @@
     const std::shared_ptr<sdbusplus::asio::connection>& asioConnection) :
     m_ioContext(ioCon), m_interface(iFace), m_asioConnection(asioConnection)
 {
-// Single FAB functionality to be included in subsequent commit.
-#ifdef IBM_SYSTEM_UNUSED
+#ifdef IBM_SYSTEM
     if (!dbusUtility::isChassisPowerOn())
     {
         SingleFab l_singleFab;