scsi: qedi: Initialize the stats mutex lock

Fix kernel NULL pointer dereference,

Call Trace:
  [<ffffffff9b7658e6>] __mutex_lock_slowpath+0xa6/0x1d0
  [<ffffffff9b764cef>] mutex_lock+0x1f/0x2f
  [<ffffffffc061b5e1>] qedi_get_protocol_tlv_data+0x61/0x450 [qedi]
  [<ffffffff9b1f9d8e>] ? map_vm_area+0x2e/0x40
  [<ffffffff9b1fc370>] ? __vmalloc_node_range+0x170/0x280
  [<ffffffffc0b81c3d>] ? qed_mfw_process_tlv_req+0x27d/0xbd0 [qed]
  [<ffffffffc0b6461b>] qed_mfw_fill_tlv_data+0x4b/0xb0 [qed]
  [<ffffffffc0b81c59>] qed_mfw_process_tlv_req+0x299/0xbd0 [qed]
  [<ffffffff9b02a59e>] ? __switch_to+0xce/0x580
  [<ffffffffc0b61e5b>] qed_slowpath_task+0x5b/0x80 [qed]
Signed-off-by: Nilesh Javali <nilesh.javali@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/qedi/qedi_main.c

@@ -2472,6 +2472,7 @@ static int __qedi_probe(struct pci_dev *pdev, int mode)
 		/* start qedi context */
 		spin_lock_init(&qedi->hba_lock);
 		spin_lock_init(&qedi->task_idx_lock);
+		mutex_init(&qedi->stats_lock);
 	}
 	qedi_ops->ll2->register_cb_ops(qedi->cdev, &qedi_ll2_cb_ops, qedi);
 	qedi_ops->ll2->start(qedi->cdev, &params);