tools: Fix bug in pldm_fwup_pkg_creator.py
tools: Fix bug in pldm_fwup_pkg_creator.py

The fix is to generate the package header checksum after updating
the package header size, which includes the checksum.

Signed-off-by: Tom Joseph <b9c6330b74e9240496e23e0ead41648ed4172ac7@gmail.com>
Change-Id: I3364ddcb1fa1d20c5abc3ae1be7562c9d9c2ed78

openbmc/pldm,openbmc/pldm,openbmc/pldm