media: tda1997x: fix get_edid

set_edid never wrote the new EDID to state->edid.edid, it was only
written to the hardware. Since get_edid returned state->edid.edid,
it was never returning the right EDID.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
[hverkuil-cisco@xs4all.nl: added missing commit log]
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>