drm/tegra: dpaux: Remove unneeded variable

Fix the following coccicheck REVIEW:
./drivers/gpu/drm/tegra/dpaux.c:282:13-16 REVIEW Unneeded variable

Reported-by: Zeal Robot <zealci@zte.com.cm>
Signed-off-by: chiminghao <chi.minghao@zte.com.cn>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/tegra/dpaux.c

@@ -280,7 +280,6 @@ static void tegra_dpaux_hotplug(struct work_struct *work)
 static irqreturn_t tegra_dpaux_irq(int irq, void *data)
 {
 	struct tegra_dpaux *dpaux = data;
-	irqreturn_t ret = IRQ_HANDLED;
 	u32 value;
 
 	/* clear interrupts */
@@ -297,7 +296,7 @@ static irqreturn_t tegra_dpaux_irq(int irq, void *data)
 	if (value & DPAUX_INTR_AUX_DONE)
 		complete(&dpaux->complete);
 
-	return ret;
+	return IRQ_HANDLED;
 }
 
 enum tegra_dpaux_functions {