ipmi: kcs_bmc: Rename {read,write}_{status,data}() functions

Rename the functions in preparation for separating the IPMI chardev out
from the KCS BMC core.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Reviewed-by: Zev Weiss <zweiss@equinix.com>
Message-Id: <20210608104757.582199-4-andrew@aj.id.au>
Signed-off-by: Corey Minyard <cminyard@mvista.com>