Revert "drm/display: Make all helpers visible and switch to depends on"

This reverts commit d674858f, as helper
code should always be selected by the driver that needs it, for the
convenience of the final user configuring a kernel.

The user who configures a kernel should not need to know which helpers
are needed for the driver he is interested in.  Making a driver depend
on helper code means that the user needs to know which helpers to enable
first, which is very user-unfriendly.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://patchwork.freedesktop.org/patch/msgid/3db958e3f4002e26cd963596d810c37feb315fb3.1713780345.git.geert+renesas@glider.be


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