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/const.hpp b/const.hpp
index 5c67968..8130334 100644
--- a/const.hpp
+++ b/const.hpp
@@ -125,6 +125,17 @@
     FAILED = -1
 };
 } // namespace eccStatus
+
+/**
+ * @brief Types of VPD
+ */
+enum vpdType
+{
+    IPZ_VPD,           /**< IPZ VPD type */
+    KEYWORD_VPD,       /**< Keyword VPD type */
+    MEMORY_VPD,        /**< Memory VPD type */
+    INVALID_VPD_FORMAT /**< Invalid VPD type */
+};
 } // namespace constants
 } // namespace vpd
 } // namespace openpower