RDMA/ocrdma: Cleanup unused device list and rcu variables

ocrdma_dev_list is not used by the driver. So removing
the references of this variable. dev->rcu was introduced
for the ipv6 notifier for GID management. This is no longer
required as the GID management is outside the HW driver.

Signed-off-by: Padmanabh Ratnakar <padmanabh.ratnakar@avagotech.com>
Signed-off-by: Selvin Xavier <selvin.xavier@avagotech.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>