media: cedrus: Fix initialization order

Currently, MEDIA_IOC_G_TOPOLOGY ioctl on cedrus fails due to incorrect
initialization order. Fix that by moving video_register_device() before
v4l2_m2m_register_media_controller() and while at it, fix error path.

Reported-by: Jonas Karlman <jonas@kwiboo.se>
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Acked-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>