PEL: peltool: Add const strings for section header

Added "Section Version", "Sub-section type" and "Created by" constant strings.

Updated all getJSON() functions to use the new constants.

Signed-off-by: Harisuddin Mohamed Isa <harisuddin@gmail.com>
Change-Id: I434192afed929972845c3cfb8876cc5ef784eec2
diff --git a/extensions/openpower-pels/user_data_json.cpp b/extensions/openpower-pels/user_data_json.cpp
index a86ccb3..f91d5f8 100644
--- a/extensions/openpower-pels/user_data_json.cpp
+++ b/extensions/openpower-pels/user_data_json.cpp
@@ -16,7 +16,9 @@
 
 #include "user_data_json.hpp"
 
+#include "json_utils.hpp"
 #include "pel_types.hpp"
+#include "pel_values.hpp"
 #include "user_data_formats.hpp"
 
 #include <fifo_map.hpp>
@@ -27,7 +29,7 @@
 
 namespace openpower::pels::user_data
 {
-
+namespace pv = openpower::pels::pel_values;
 using namespace phosphor::logging;
 
 // Use fifo_map as nlohmann::json's map. We are just ignoring the 'less'
@@ -51,12 +53,9 @@
                        const fifoJSON& json)
 {
     fifoJSON output;
-    output["Section Version"] = std::to_string(version);
-    output["Sub-section type"] = std::to_string(subType);
-
-    char value[10];
-    sprintf(value, "0x%04X", componentID);
-    output["Created by"] = std::string{value};
+    output[pv::sectionVer] = std::to_string(version);
+    output[pv::subSection] = std::to_string(subType);
+    output[pv::createdBy] = getNumberString("0x%04X", componentID);
 
     if (!json.is_object())
     {