[media] adv7842: platform-data for Hotplug Active (HPA) manual/auto

This applies to HDMI-map register 0x69.
So far we have been using HPA manual mode.
This way we had control of HPA which could be
set after EDID had been programmed.

Using a Mac Mini with mini-displayport to DVI-D converter as source
caused the adv7842 to lock up and fail to detect any further signals.

After experimenting with different configurations it was found that
using the HPA auto mode and in addition letting RX-termination
be controlled by HPA prevented this error from occuring.

I was not able to re-create this problem on the adv7604.

Signed-off-by: Martin Bugge <marbugge@cisco.com>
Cc: Mats Randgaard <matrandg@cisco.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>