media: adv7604: writing a one-block EDID failed

The adv7604 refused to accept an one-block EDID, it required two blocks.

Fix this.

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