media: em28xx: annotate unchecked call to media_device_register()

[ Upstream commit fd61d77a3d28444b2635f0c8b5a2ecd6a4d94026 ]

Static analyzers generate alerts for an unchecked call to
`media_device_register()`. However, in this case, the device will work
reliably without the media controller API.

Add a comment above the call to prevent future unnecessary changes.

Suggested-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Fixes: 37ecc7b ("[media] em28xx: add media controller support")
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/media/usb/em28xx/em28xx-cards.c

@@ -4094,6 +4094,10 @@ static int em28xx_usb_probe(struct usb_interface *intf,
 	 * topology will likely change after the load of the em28xx subdrivers.
 	 */
 #ifdef CONFIG_MEDIA_CONTROLLER
+	/*
+	 * No need to check the return value, the device will still be
+	 * usable without media controller API.
+	 */
 	retval = media_device_register(dev->media_dev);
 #endif