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>
 static irqreturn_t tegra_dpaux_irq(int irq, void *data)
 {
        struct tegra_dpaux *dpaux = data;
-       irqreturn_t ret = IRQ_HANDLED;
        u32 value;
 
        /* clear interrupts */
        if (value & DPAUX_INTR_AUX_DONE)
                complete(&dpaux->complete);
 
-       return ret;
+       return IRQ_HANDLED;
 }
 
 enum tegra_dpaux_functions {