V4L/DVB: sh_mobile_ceu_camera: fix debugging message

With enabled debugging sh_mobile_ceu_camera.c dereferences an invalid or a NULL
pointer. Thanks to James Wang for reporting.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>