drm/vc4: hdmi: Remove DDC argument to connector_init

Now that we are passing the vc4_hdmi structure to the connector init
function, we can simply use the pointer in that structure instead of
having the pointer as an argument.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Tested-by: Chanwoo Choi <cw00.choi@samsung.com>
Tested-by: Hoegeun Kwon <hoegeun.kwon@samsung.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/4fe1b45fe45e4ba57d40154da010807d4e5db86c.1599120059.git-series.maxime@cerno.tech