RDMA/ocrdma: Handle shutdown event from be2net driver

be2net driver sends a shutdown event to ocrdma during shutdown/reboot.
As part of event processing, ocrdma calls close() and remove() to free
all the resources associated with ocrdma. This also frees irqs used by
ocrdma.

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