media: test-drivers: Stop direct calls to queue num_buffers field

Use vb2_get_num_buffers() to avoid using queue num_buffers field directly.
This allows us to change how the number of buffers is computed in the
future.
If 'min_buffers_needed' is set remove useless checks in queue setup
functions.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
CC: Daniel Almeida <daniel.almeida@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

media: vivid: Fix global-out-of-bounds read in precalculate_color()

vivid_meta_out_process() is setting `brightness`, `contrast`, `saturation`
and `hue` using tpg_s_*(). This is wrong, since tpg_s_*() do not provide
range checks. Using tpg_s_*() here also makes the control framework
out-of-sync with the actual values. Use v4l2_ctrl_s_ctrl() instead.

This issue has been reported by syzbot as an out-of-bounds read bug in
precalculate_color().

Reported-and-tested-by: syzbot+02d9172bf4c43104cd70@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=02d9172bf4c43104cd70

Fixes: 746facd39370 ("media: vivid: Add metadata output support")
Suggested-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: media/test_drivers: rename to test-drivers

We never use _ in directory names in the media subsystem, so
rename to test-drivers instead for consistency.

Also update MAINTAINERS with the new path.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>