RDMA/ocrdma: Unregister inet notifier when unloading ocrdma

Unregister the inet notifier during ocrdma unload to avoid a panic after
driver unload.

Signed-off-by: Selvin Xavier <selvin.xavier@emulex.com>
Signed-off-by: Devesh Sharma <devesh.sharma@emulex.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>