scsi: qla2xxx: Fix error handling in qlt_alloc_qfull_cmd()

The test "if (!cmd)" is not useful because it is guaranteed that cmd !=
NULL.  Instead of testing the cmd pointer, rely on the tag to decide
whether or not command allocation failed.

Cc: Himanshu Madhani <hmadhani@marvell.com>
Cc: Giridhar Malavali <gmalavali@marvell.com>
Fixes: 33e79977 ("qla2xxx: Add support for QFull throttling and Term Exchange retry") # v3.18.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: Himanshu Madhani <hmadhani@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/qla2xxx/qla_target.c

@@ -5481,11 +5481,7 @@ qlt_alloc_qfull_cmd(struct scsi_qla_host *vha,
 	se_sess = sess->se_sess;
 
 	tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);
-	if (tag < 0)
-		return;
-
-	cmd = &((struct qla_tgt_cmd *)se_sess->sess_cmd_map)[tag];
-	if (!cmd) {
+	if (tag < 0) {
 		ql_dbg(ql_dbg_io, vha, 0x3009,
 			"qla_target(%d): %s: Allocation of cmd failed\n",
 			vha->vp_idx, __func__);
@@ -5500,6 +5496,7 @@ qlt_alloc_qfull_cmd(struct scsi_qla_host *vha,
 		return;
 	}
 
+	cmd = &((struct qla_tgt_cmd *)se_sess->sess_cmd_map)[tag];
 	memset(cmd, 0, sizeof(struct qla_tgt_cmd));
 
 	qlt_incr_num_pend_cmds(vha);