[media] dib9000: fix potential format string leak

Make sure that a format string cannot accidentally
leak into the printk buffer.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>