[SCSI] bfa: Fix possible NULL pointer dereference in lunmask add/delete.

Patch fixes the possible NULL pointer dereference when we try to add or delete
a rpwwn to the lunmask config which is not zoned to this port.  Check if the
FCS rport is not NULL before de-referencing it.
Signed-off-by: Krishna Gudipati <kgudipat@brocade.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/bfa/bfa_fcpim.c

@@ -2647,6 +2647,7 @@ bfa_fcpim_lunmask_add(struct bfa_s *bfa, u16 vf_id, wwn_t *pwwn,
 	if (port) {
 		*pwwn = port->port_cfg.pwwn;
 		rp_fcs = bfa_fcs_lport_get_rport_by_pwwn(port, rpwwn);
+		if (rp_fcs)
 			rp = rp_fcs->bfa_rport;
 	}
 
@@ -2715,6 +2716,7 @@ bfa_fcpim_lunmask_delete(struct bfa_s *bfa, u16 vf_id, wwn_t *pwwn,
 		if (port) {
 			*pwwn = port->port_cfg.pwwn;
 			rp_fcs = bfa_fcs_lport_get_rport_by_pwwn(port, rpwwn);
+			if (rp_fcs)
 				rp = rp_fcs->bfa_rport;
 		}
 	}