V4L/DVB: video/au0828: off by one bug

The "AUVI_INPUT(tmp)" macro uses "tmp" as an index of an array with
AU0828_MAX_INPUT elements.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>