crypto: picoxcell - Fix potential race condition bug

engine->stat_irq_thresh was initialized after device_create_file() in
the probe function, the initialization may race with call to
spacc_stat_irq_thresh_store() which updates engine->stat_irq_thresh,
therefore initialize it before creating the file in probe function.

Found by Linux Driver Verification project (linuxtesting.org).

Fixes: ce921368 ("crypto: picoxcell - add support for the...")
Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Acked-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/picoxcell_crypto.c

@@ -1685,11 +1685,6 @@ static int spacc_probe(struct platform_device *pdev)
 		goto err_clk_put;
 	}
 
-	ret = device_create_file(&pdev->dev, &dev_attr_stat_irq_thresh);
-	if (ret)
-		goto err_clk_disable;
-
-
 	/*
 	 * Use an IRQ threshold of 50% as a default. This seems to be a
 	 * reasonable trade off of latency against throughput but can be
@@ -1697,6 +1692,10 @@ static int spacc_probe(struct platform_device *pdev)
 	 */
 	engine->stat_irq_thresh = (engine->fifo_sz / 2);
 
+	ret = device_create_file(&pdev->dev, &dev_attr_stat_irq_thresh);
+	if (ret)
+		goto err_clk_disable;
+
 	/*
 	 * Configure the interrupts. We only use the STAT_CNT interrupt as we
 	 * only submit a new packet for processing when we complete another in