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.org


Signed-off-by: Maxime Ripard <mripard@kernel.org>