V4L/DVB (11758): 2: handle unregister for non-I2C builds

Build fails when CONFIG_I2C=n, so handle that case in the if block:

drivers/built-in.o: In function `v4l2_device_unregister':
(.text+0x157821): undefined reference to `i2c_unregister_device'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/v4l2-device.c

@@ -85,6 +85,7 @@ void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
 	/* Unregister subdevs */
 	list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) {
 		v4l2_device_unregister_subdev(sd);
+#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
 		if (sd->flags & V4L2_SUBDEV_FL_IS_I2C) {
 			struct i2c_client *client = v4l2_get_subdevdata(sd);
 
@@ -95,6 +96,7 @@ void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
 			if (client)
 				i2c_unregister_device(client);
 		}
+#endif
 	}
 }
 EXPORT_SYMBOL_GPL(v4l2_device_unregister);