media: v4l2-dv-timings.c: fix wrong condition in two for-loops

media: v4l2-dv-timings.c: fix wrong condition in two for-loops

These for-loops should test against v4l2_dv_timings_presets[i].bt.width,
not if i < v4l2_dv_timings_presets[i].bt.width. Luckily nothing ever broke,
since the smallest width is still a lot higher than the total number of
presets, but it is wrong.

The last item in the presets array is all 0, so the for-loop must stop
when it reaches that sentinel.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reported-by: Krzysztof Hałasa <khalasa@piap.pl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>