[media] lg2160: dubious one-bit signed bitfield

Sparse complains that these are "dubious one-bit signed bitfields" and
the comment says it was intended to be 1 and 0 instead of -1 and 0.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>