media: sunxi: cedrus: Fix missing error message context

When cedrus_hw_probe is called, v4l2_dev is not yet initialized.
Use dev_err instead.

Signed-off-by: Ondrej Jirman <megous@megous.com>
Acked-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>