drm/sun4i: dw-hdmi: Fix ddc-en GPIO consumer conflict

commit 6de79dd3 ("drm/bridge: display-connector: add ddc-en gpio
support") added a consumer for this GPIO in the HDMI connector device.
This new consumer conflicts with the pre-existing GPIO consumer in the
sun8i HDMI controller driver, which prevents the driver from probing:

  [    4.983358] display-connector connector: GPIO lookup for consumer ddc-en
  [    4.983364] display-connector connector: using device tree for GPIO lookup
  [    4.983392] gpio-226 (ddc-en): gpiod_request: status -16
  [    4.983399] sun8i-dw-hdmi 6000000.hdmi: Couldn't get ddc-en gpio
  [    4.983618] sun4i-drm display-engine: failed to bind 6000000.hdmi (ops sun8i_dw_hdmi_ops [sun8i_drm_hdmi]): -16
  [    4.984082] sun4i-drm display-engine: Couldn't bind all pipelines components
  [    4.984171] sun4i-drm display-engine: adev bind failed: -16
  [    4.984179] sun8i-dw-hdmi: probe of 6000000.hdmi failed with error -16

Both drivers have the same behavior: they leave the GPIO active for the
life of the device. Let's take advantage of the new implementation, and
drop the now-obsolete code from the HDMI controller driver.

Fixes: 6de79dd3

 ("drm/bridge: display-connector: add ddc-en gpio support")
Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20220614073100.11550-1-samuel@sholland.org