target: Remove unnecessary *cdb transport_get_lun_for_cmd parameter

This patch removes the now unnecessary 'unsigned char *cdb' function
parameter from transport_get_lun_for_cmd().  This also includes updating
lio-target, tcm_loop and tcm_fc usage of transport_get_lun_for_cmd().

Reported-by: Fubo Chen <fubo.chen@gmail.com>
Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/tcm_fc/tfc_cmd.c b/drivers/target/tcm_fc/tfc_cmd.c
index b2a1067..92a449a 100644
--- a/drivers/target/tcm_fc/tfc_cmd.c
+++ b/drivers/target/tcm_fc/tfc_cmd.c
@@ -637,7 +637,7 @@
 	fc_seq_exch(cmd->seq)->lp->tt.seq_set_resp(cmd->seq, ft_recv_seq, cmd);
 
 	cmd->lun = scsilun_to_int((struct scsi_lun *)fcp->fc_lun);
-	ret = transport_get_lun_for_cmd(&cmd->se_cmd, NULL, cmd->lun);
+	ret = transport_get_lun_for_cmd(&cmd->se_cmd, cmd->lun);
 	if (ret < 0) {
 		ft_dump_cmd(cmd, __func__);
 		transport_send_check_condition_and_sense(&cmd->se_cmd,