test: cleanup: firmware::write() tests
test: cleanup: firmware::write() tests

Signed-off-by: Patrick Venture <36c53fa43f47f3fd67cb2fc38031827244d18a1f@google.com>
Change-Id: I1a186b0491152f9919de2e9dd43cb68d7de29bda

openbmc/phosphor-ipmi-flash