staging: media: starfive: Remove links when unregistering devices

Need to remove links when unregistering devices.

Fixes: ac7da4a7 ("media: staging: media: starfive: camss: Register devices")

Signed-off-by: Changhuang Liang <changhuang.liang@starfivetech.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>