drm/display: stop depending on DRM_DISPLAY_HELPER

Kconfig symbols should not declare dependency on DRM_DISPLAY_HELPER.
Move all parts of DRM_DISPLAY_HELPER to an if DRM_DISPLAY_HELPER block.

It is not possible to make those symbols select DRM_DISPLAY_HELPER
because of the link issues when a part of the helper is selected to be
built-in, while other part is selected to be as module. In such a case
the modular part doesn't get built at all, leading to undefined symbols.

The only viable alternative is to split drm_display_helper.ko into
several small modules, each of them having their own dependencies.
Suggested-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240903-drm-bridge-connector-fix-hdmi-reset-v5-1-daebde6d9857@linaro.orgSigned-off-by: Maxime Ripard <mripard@kernel.org>

drivers/gpu/drm/display/Kconfig

 # SPDX-License-Identifier: MIT
 
+config DRM_DISPLAY_DP_AUX_BUS
+	tristate
+	depends on DRM
+	depends on OF || COMPILE_TEST
+
 config DRM_DISPLAY_HELPER
 	tristate
 	depends on DRM
 	help
 	  DRM helpers for display adapters.
 
-config DRM_DISPLAY_DP_AUX_BUS
-	tristate
-	depends on DRM
-	depends on OF || COMPILE_TEST
+if DRM_DISPLAY_HELPER
 
 config DRM_DISPLAY_DP_AUX_CEC
 	bool "Enable DisplayPort CEC-Tunneling-over-AUX HDMI support"
-	depends on DRM && DRM_DISPLAY_HELPER
 	select DRM_DISPLAY_DP_HELPER
 	select CEC_CORE
 	help
@@ -25,7 +26,6 @@ config DRM_DISPLAY_DP_AUX_CEC
 
 config DRM_DISPLAY_DP_AUX_CHARDEV
 	bool "DRM DP AUX Interface"
-	depends on DRM && DRM_DISPLAY_HELPER
 	select DRM_DISPLAY_DP_HELPER
 	help
 	  Choose this option to enable a /dev/drm_dp_auxN node that allows to
@@ -34,7 +34,6 @@ config DRM_DISPLAY_DP_AUX_CHARDEV
 
 config DRM_DISPLAY_DP_HELPER
 	bool
-	depends on DRM_DISPLAY_HELPER
 	help
 	  DRM display helpers for DisplayPort.
 
@@ -61,19 +60,18 @@ config DRM_DISPLAY_DP_TUNNEL_STATE_DEBUG
 
 config DRM_DISPLAY_HDCP_HELPER
 	bool
-	depends on DRM_DISPLAY_HELPER
 	help
 	  DRM display helpers for HDCP.
 
 config DRM_DISPLAY_HDMI_HELPER
 	bool
-	depends on DRM_DISPLAY_HELPER
 	help
 	  DRM display helpers for HDMI.
 
 config DRM_DISPLAY_HDMI_STATE_HELPER
 	bool
-	depends on DRM_DISPLAY_HELPER
 	select DRM_DISPLAY_HDMI_HELPER
 	help
 	  DRM KMS state helpers for HDMI.
+
+endif # DRM_DISPLAY_HELPER