media: tc358743: ignore video while HPD is low

If the HPD is low (happens if there is no EDID or the
EDID is being updated), then return -ENOLINK in
tc358743_get_detected_timings() instead of detecting video.

This avoids userspace thinking that it can start streaming when
the HPD is low.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Tested-by: Maxime Ripard <mripard@kernel.org>
Link: https://lore.kernel.org/linux-media/20240628-stoic-bettong-of-fortitude-e25611@houat/


Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>