[PATCH] Small fix in eeh definitions when CONFIG_EEH not enabled

Undefined symbols (eeh_add_device_tree_early and eeh_remove_bus_device)
when EEH is not enabled. This small patch will fix this.

Acked-by: Linas Vepstas <linas@austin.ibm.com>

Signed-off-by: Paul Mackerras <paulus@samba.org>