[media] atomisp: putting NULs in the wrong place

We're putting the NUL terminators one space beyond where they belong.
This doesn't show up in testing because all but the callers put a NUL in
the correct place themselves.  LOL.  It causes a static checker warning
about buffer overflows.

Fixes: a49d2536 ("staging/atomisp: Add support for the Intel IPU v2")

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>