drm/rockchip: analogix_dp: add rk3399 eDP support

RK3399 and RK3288 shared the same eDP IP controller, only some light
difference with VOP configure and GRF configure.

Signed-off-by: Yakir Yang <ykk@rock-chips.com>
Acked-by: Mark Yao <mark.yao@rock-chips.com>
Reviewed-by: Tomasz Figa <tomasz.figa@chromium.com>
Reviewed-by: Sean Paul <seanpaul@chromium.org>

include/drm/bridge/analogix_dp.h

@@ -16,11 +16,12 @@
 enum analogix_dp_devtype {
 	EXYNOS_DP,
 	RK3288_DP,
+	RK3399_EDP,
 };
 
 static inline bool is_rockchip(enum analogix_dp_devtype type)
 {
-	return type == RK3288_DP;
+	return type == RK3288_DP || type == RK3399_EDP;
 }
 
 struct analogix_dp_plat_data {