FROMLIST: drm/rockchip: dw_hdmi: Call drm_encoder_cleanup() in error path

FROMLIST: drm/rockchip: dw_hdmi: Call drm_encoder_cleanup() in error path

The drm_encoder_cleanup() was missing both from the error path of
dw_hdmi_rockchip_bind().  This caused a crash when slub_debug was
enabled and we ended up deferring probe of HDMI at boot.

This call isn't needed from unbind() because if dw_hdmi_bind() returns
no error then it takes over the job of freeing the encoder (in
dw_hdmi_unbind).

(am from https://patchwork.kernel.org/patch/8523331/)

Change-Id: Ibf5c39a5db304177a9f16d8dc691221512002348
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Mark Yao <mark.yao@rock-chips.com>