memory: samsung: exynos5422-dmc: Reduce protected code area in IRQ handler

Speed-up a bit this IRQ processing as there is no need to protect
return value or printing.
Signed-off-by: Bernard Zhao <bernard@vivo.com>
Acked-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

drivers/memory/samsung/exynos5422-dmc.c

@@ -1346,15 +1346,13 @@ static irqreturn_t dmc_irq_thread(int irq, void *priv)
 	struct exynos5_dmc *dmc = priv;
 
 	mutex_lock(&dmc->df->lock);
-
 	exynos5_dmc_perf_events_check(dmc);
-
 	res = update_devfreq(dmc->df);
+	mutex_unlock(&dmc->df->lock);
+
 	if (res)
 		dev_warn(dmc->dev, "devfreq failed with %d\n", res);
 
-	mutex_unlock(&dmc->df->lock);
-
 	return IRQ_HANDLED;
 }