media: vimc: wrong pointer is used with PTR_ERR

Fix smatch warning:

drivers/media/test-drivers/vimc/vimc-core.c:214 vimc_create_links() warn: passing a valid pointer to 'PTR_ERR'

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>