RDMA/ocrdma: Host crash on destroying device resources

1. Cleanup sequence in ocrdma_remove(). The device should be
   unregistered from IB stack before any device specific cleanup.
2. Always return success in the resource destroy path. In case destroy
   command returns error, IB stack will trigger cleanup again while
   closing the uverbs device causing kernel panic BUG_ON().

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