drm/bridge: analogix_dp: Move enable video into config_video()

We need to enable video before analogix_dp_is_video_stream_on(), so
we can get the right video stream status.

We needed to increase the delay in the timeout loop because there is
random "Timeout of video streamclk ok" message happen when debug edp
panel, this time do not define in the spec.

Cc: 征增 王 <wzz@rock-chips.com>
Cc: Stéphane Marchesin <marcheu@chromium.org>
Signed-off-by: Lin Huang <hl@rock-chips.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180423105003.9004-2-enric.balletbo@collabora.com