Make the following properties per-input

-DV Timings Signal Mode
-DV Timings

These properties need to be per-input in order to implement proper
HDMI (dis)connect-behavior, where the signal mode will be used to
signify whether or not there is an input device connected.
Signed-off-by: Johan Korsnes <johan.korsnes@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>