README: typo fix s/differnet/different/
README: typo fix s/differnet/different/

Signed-off-by: Patrick Venture <36c53fa43f47f3fd67cb2fc38031827244d18a1f@google.com>
Change-Id: I4f00d0d7581fca78bc9e23f3db55c36aac254096

openbmc/phosphor-ipmi-flash