Get inventory list using expanded location code

This commit implements api to get inventory list with respect to
a given location code in expanded format.

In case no inventory is found at the given location or location code
is not correct, corresponding error is returned to the caller.

Tested on simics.
This api is under com.ibm.vpd.Manager interface. So vpd-manager app
needs to be running for this api to work.
Sample command for simics:
busctl call com.ibm.VPD.Manager /com/ibm/VPD/Manager com.ibm.VPD.Manager
GetFRUsByUnexpandedLocationCode sq <location_code> <node_number>

Signed-off-by: Sunny Srivastava <sunnsr25@in.ibm.com>
Change-Id: Ifa47d73a64338cbd228b5be1346027c69695612a
diff --git a/const.hpp b/const.hpp
index fc93468..c2ff5b3 100644
--- a/const.hpp
+++ b/const.hpp
@@ -43,6 +43,9 @@
 constexpr uint8_t KW_VAL_PAIR_START_TAG = 0x84;
 constexpr uint8_t RECORD_END_TAG = 0x78;
 constexpr int UNEXP_LOCATION_CODE_MIN_LENGTH = 4;
+constexpr uint8_t EXP_LOCATIN_CODE_MIN_LENGTH = 17;
+static constexpr auto SE_KWD_LENGTH = 7;
+static constexpr auto INVALID_NODE_NUMBER = -1;
 
 namespace lengths
 {