media: au0828: fix a NULL vs IS_ERR() check

The media_device_usb_allocate() function returns error pointers when
it's enabled and something goes wrong.  It can return NULL as well, but
only if CONFIG_MEDIA_CONTROLLER is disabled so that doesn't apply here.

Fixes: 812658d8 ("media: change au0828 to use Media Device Allocator API")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/usb/au0828/au0828-core.c

@@ -199,8 +199,8 @@ static int au0828_media_device_init(struct au0828_dev *dev,
 	struct media_device *mdev;
 
 	mdev = media_device_usb_allocate(udev, KBUILD_MODNAME, THIS_MODULE);
-	if (!mdev)
-		return -ENOMEM;
+	if (IS_ERR(mdev))
+		return PTR_ERR(mdev);
 
 	dev->media_dev = mdev;
 #endif