CHROMIUM: drm: bridge/dw_hdmi: Provide an of_node to DDC i2c bus

CHROMIUM: drm: bridge/dw_hdmi: Provide an of_node to DDC i2c bus

In (3b9ba9a FROMLIST: drm: bridge/dw_hdmi: add dw hdmi i2c bus adapter
support) we added a new i2c bus adapter but no of_node was provided to
the adapter.  This made it difficult to assign a bus number to the
adapter in the device tree.

Because of the fact that dynamic bus numbering of i2c starts at 0 and
the fact that i2c busses are no longer allowed to be loaded extra-early
at boot (because deferred probe solves the boot order problem), it's
possible that this could cause the DDC i2c bus to get ID 0 and could
cause later SoC i2c busses to fail to probe because they're expecting to
get ID 0.

Note that probe ordering of mickey is slightly different than probe
ordering of other veyron devices, which is why this only shows up on
mickey.

BUG=chrome-os-partner:44802
TEST=With dts patch can now boot mickey again

Change-Id: I8f971a967f398ab58a6713a2b6471a4a2fe61dc6
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/297040
Reviewed-by: Alexandru Stan <amstan@chromium.org>
Signed-off-by: Yakir Yang <ykk@rock-chips.com>