Handling FRU and Module in vpd read code

Misc changes to handle reading of CPU VPD.

Change-Id: Ia8143dec680bbfeecb1e63505650428103192157
Signed-off-by: Alpana Kumari <alpankum@in.ibm.com>
diff --git a/const.hpp b/const.hpp
index 6153410..591043e 100644
--- a/const.hpp
+++ b/const.hpp
@@ -21,6 +21,7 @@
 using LE2ByteData = uint16_t;
 using DataOffset = uint16_t;
 
+static constexpr auto NEXT_64_KB = 65536;
 static constexpr auto MAC_ADDRESS_LEN_BYTES = 6;
 static constexpr auto LAST_KW = "PF";
 static constexpr auto POUND_KW = '#';