drm/bridge: analogix_dp: Move fast link training detect to set_bridge

It's too early to detect fast link training, if other step after it
failed, we will set fast_link flag to 1, and retry set_bridge again. In
this case we will power down and power up panel power supply, and we
will do fast link training since we have set fast_link flag to 1. In
fact, we should do full link training now, not the fast link training.
So we should move the fast link detection at the end of set_bridge.

Cc: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: zain wang <wzz@rock-chips.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
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>
Reviewed-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180423105003.9004-18-enric.balletbo@collabora.com