ipmi: kcs_bmc_aspeed: Fix IBFIE typo from datasheet

Input Buffer Full Interrupt Enable (IBFIE) is typoed as IBFIF for some
registers in the datasheet. Fix the driver to use the sensible acronym.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Reviewed-by: Zev Weiss <zweiss@equinix.com>
Message-Id: <20210608104757.582199-16-andrew@aj.id.au>
Signed-off-by: Corey Minyard <cminyard@mvista.com>