be2iscsi: Remove be_mbox_notify_wait function

be_mbox_notify_wait does exactly same thing as be_mbox_notify.

Signed-off-by: Jitendra Bhivare <jitendra.bhivare@broadcom.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>