media: adv7842: support 1 block EDIDs, fix clearing EDID

Add support for EDIDs consisting of one EDID block.

Related to this, improve CEC physical address handling.

Clearing the EDID caused a bug since v4l2_calc_aspect_ratio() was
called with a NULL pointer.

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