target: Add SCF_SCSI_TMR_CDB usage and drop se_tmr_req_cache

Change the test for if a cmd is a tmr request to checking if
SCF_SCSI_TMR_CDB (a new flag) is set in cmd->se_cmd_flags.

Also remove se_tmr_req_cache usage in favor of kzalloc usage,
and make core_tmr_alloc_req() return int + setup se_cmd->se_tmr_req
directly and fix up various fabric module usages

Cc: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c
index 11287e1..4eba86d 100644
--- a/drivers/target/iscsi/iscsi_target_util.c
+++ b/drivers/target/iscsi/iscsi_target_util.c
@@ -229,6 +229,7 @@
 {
 	struct iscsi_cmd *cmd;
 	struct se_cmd *se_cmd;
+	int rc;
 	u8 tcm_function;
 
 	cmd = iscsit_allocate_cmd(conn, GFP_KERNEL);
@@ -286,10 +287,8 @@
 		goto out;
 	}
 
-	se_cmd->se_tmr_req = core_tmr_alloc_req(se_cmd,
-				cmd->tmr_req, tcm_function,
-				GFP_KERNEL);
-	if (!se_cmd->se_tmr_req)
+	rc = core_tmr_alloc_req(se_cmd, cmd->tmr_req, tcm_function, GFP_KERNEL);
+	if (rc < 0)
 		goto out;
 
 	cmd->tmr_req->se_tmr_req = se_cmd->se_tmr_req;