drm: bridge: analogix/dp: rename register constants

In the original split we kept the register constants intact to keep the

diff small. Still the constants are Analogix-specific, so rename them now.
Tested-by: Caesar Wang <wxt@rock-chips.com>
Tested-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Yakir Yang <ykk@rock-chips.com>