Segregate utility methods

This commit segregates utility methods required commonly by both
openpower-read-vpd and ibm-read-vpd from methods only required by
ibm-read-vpd.
All dependency required by utility methods specific to ibm-read-vpd
is not applicable to utility methods required by openpower-read-vpd.

Hence to avoid un-necessary dependency inclusion, this change is
introduced.

Signed-off-by: Sunny Srivastava <sunnsr25@in.ibm.com>
Change-Id: I95f2be27dc0c391a45beb1654a99506317aaa52b
diff --git a/writefru.mako.hpp b/writefru.mako.hpp
index 203d033..6e04649 100755
--- a/writefru.mako.hpp
+++ b/writefru.mako.hpp
@@ -10,7 +10,7 @@
 #include "defines.hpp"
 #include "store.hpp"
 #include "types.hpp"
-#include "utils.hpp"
+#include "common_utility.hpp"
 #include "extra-properties-gen.hpp"
 
 namespace openpower
@@ -19,6 +19,7 @@
 {
 namespace inventory
 {
+using namespace openpower::vpd::common::utility;
 
 /** @brief API to write parsed VPD to inventory,
  *      for a specific FRU