[SCSI] bnx2i: Created an active linklist which holds bnx2i endpoints

This introduces a new active linklist which would link up all active
bnx2i_endpoints.  This will be used by subsequent patches that
follows.

Signed-off-by: Eddie Wai <eddie.wai@broadcom.com>
Reviewed-by: Michael Chan <mchan@broadcom.com>
Reviewed-by: Benjamin Li <benli@broadcom.com>
Acked-by: Anil Veerabhadrappa <anilgv@broadcom.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>