virtio: remove export for virtio_config_{enable, disable}

virtio_config_enable(), virtio_config_disable() are only used inside
drivers/virtio/virtio.c, so it doesn't need export the symbols.

Signed-off-by: Xianting Tian <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Michael S. Tsirkin <[e-mail]>
Acked-by: Jason Wang <[e-mail]>
Reviewed-by: Stefano Garzarella <[e-mail]>

drivers/virtio/virtio.c

···
 }
 EXPORT_SYMBOL_GPL(virtio_config_changed);
 
-void virtio_config_disable(struct virtio_device *dev)
+static void virtio_config_disable(struct virtio_device *dev)
 {
 	spin_lock_irq(&dev->config_lock);
 	dev->config_enabled = false;
 	spin_unlock_irq(&dev->config_lock);
 }
-EXPORT_SYMBOL_GPL(virtio_config_disable);
 
-void virtio_config_enable(struct virtio_device *dev)
+static void virtio_config_enable(struct virtio_device *dev)
 {
 	spin_lock_irq(&dev->config_lock);
 	dev->config_enabled = true;
···
 	dev->config_change_pending = false;
 	spin_unlock_irq(&dev->config_lock);
 }
-EXPORT_SYMBOL_GPL(virtio_config_enable);
 
 void virtio_add_status(struct virtio_device *dev, unsigned int status)
 {

include/linux/virtio.h

···
 void virtio_break_device(struct virtio_device *dev);
 
 void virtio_config_changed(struct virtio_device *dev);
-void virtio_config_disable(struct virtio_device *dev);
-void virtio_config_enable(struct virtio_device *dev);
 int virtio_finalize_features(struct virtio_device *dev);
 #ifdef CONFIG_PM_SLEEP
 int virtio_device_freeze(struct virtio_device *dev);