char: ipmi: Move MODULE_DEVICE_TABLE() to follow struct

The policy for drivers is to have MODULE_DEVICE_TABLE() just after the
struct used in it. For clarity.

Suggested-by: Corey Minyard <minyard@acm.org>
Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>