PEL: Fix hexdump output in peltool

Hexdump output of UserData section has 8 extra bytes that are not part
of the section data. This fix truncates the extra data to show the true
hexdump output.

Signed-off-by: Harisuddin Mohamed Isa <harisuddin@gmail.com>
Change-Id: I7c0b46fb85b94265ae4f960eb4ef36eaf293db3b
diff --git a/extensions/openpower-pels/pel.cpp b/extensions/openpower-pels/pel.cpp
index f94a1fc..0845aba 100644
--- a/extensions/openpower-pels/pel.cpp
+++ b/extensions/openpower-pels/pel.cpp
@@ -311,8 +311,7 @@
             section.flatten(s);
             std::string dstr =
                 dumpHex(std::data(data) + SectionHeader::flattenedSize(),
-                        data.size(), 2);
-
+                        data.size() - SectionHeader::flattenedSize(), 2);
             std::string jsonIndent(indentLevel, 0x20);
             buf += jsonIndent + "\"Data\": [\n";
             buf += dstr;