staging: pi433: Remove unnecessary variable

The variable retval is assigned constant values twice, and can therefore
be replaced by its values.

Signed-off-by: Nishka Dasgupta <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/pi433/pi433_if.c

···
 static long
 pi433_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
-	int			retval = 0;
 	struct pi433_instance	*instance;
 	struct pi433_device	*device;
 	struct pi433_tx_cfg	tx_cfg;
···
 		mutex_unlock(&device->rx_lock);
 		break;
 	default:
-		retval = -EINVAL;
+		return -EINVAL;
 	}
 
-	return retval;
+	return 0;
 }
 
 #ifdef CONFIG_COMPAT