scsi: cxgb4i: add wait_for_completion()

In case of ->set_param() and ->bind_conn() cxgb4i driver does not wait for
cmd completion, this can create race conditions, to avoid this add
wait_for_completion().

Signed-off-by: Varun Prakash <varun@chelsio.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>