[PATCH -next] drm/rockchip: Fix Kconfig dependencies

[Ren Zhijie <renzhijie2@huawei.com>]

If CONFIG_ROCKCHIP_ANALOGIX_DP is not set, the rockchip drm driver
will fail to link:

drivers/gpu/drm/rockchip/cdn-dp-core.o: In function `cdn_dp_connector_mode_valid':
cdn-dp-core.c:(.text+0x1e1): undefined reference to `drm_dp_bw_code_to_link_rate'
cdn-dp-core.c:(.text+0x1f4): undefined reference to `drm_dp_bw_code_to_link_rate'
drivers/gpu/drm/rockchip/cdn-dp-core.o: In function `cdn_dp_pd_event_work':
cdn-dp-core.c:(.text+0x138e): undefined reference to `drm_dp_channel_eq_ok'
drivers/gpu/drm/rockchip/cdn-dp-reg.o: In function `cdn_dp_train_link':
cdn-dp-reg.c:(.text+0xd5a): undefined reference to `drm_dp_bw_code_to_link_rate'

The problem is that the DP-helper module has been replaced by the display-helper module.
So the driver have to select it.

Reported-by: Hulk Robot <hulkci@huawei.com>
Fixes: 1e0f66420b13("drm/display: Introduce a DRM display-helper module")
Signed-off-by: Ren Zhijie <renzhijie2@huawei.com>
---
 drivers/gpu/drm/rockchip/Kconfig | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/rockchip/Kconfig b/drivers/gpu/drm/rockchip/Kconfig
index 5afab49dc4f2..eb9ffa9e357d 100644
--- a/drivers/gpu/drm/rockchip/Kconfig
+++ b/drivers/gpu/drm/rockchip/Kconfig
@@ -47,6 +47,8 @@ config ROCKCHIP_ANALOGIX_DP
 config ROCKCHIP_CDN_DP
 	bool "Rockchip cdn DP"
 	depends on EXTCON=y || (EXTCON=m && DRM_ROCKCHIP=m)
+	select DRM_DISPLAY_HELPER
+	select DRM_DISPLAY_DP_HELPER
 	help
 	  This selects support for Rockchip SoC specific extensions
 	  for the cdn DP driver. If you want to enable Dp on
-- 
2.17.1