ipmi: Make some data const that was only read

Several data structures were only used for reading, so make them
const.

Signed-off-by: Corey Minyard <cminyard@mvista.com>

diff --cc drivers/char/ipmi/ipmi_bt_sm.c
Simple merge

diff --cc drivers/char/ipmi/ipmi_kcs_sm.c
Simple merge

diff --cc drivers/char/ipmi/ipmi_msghandler.c
Simple merge

diff --cc drivers/char/ipmi/ipmi_si_intf.c
Simple merge

diff --cc drivers/char/ipmi/ipmi_si_sm.h
Simple merge

diff --cc drivers/char/ipmi/ipmi_smic_sm.c
Simple merge

diff --cc include/linux/ipmi_smi.h
Simple merge