ipmi: add of_device_id in MODULE_DEVICE_TABLE

Fix autoloading ipmi modules when using device tree.

Signed-off-by: Brijesh Singh <brijeshkumar.singh@amd.com>

Moved this change up into the CONFIG_OF section to account
for changes to the probing code.

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