ARM: dts: exynos: Use i2c-gpio for HDMI-DDC on Arndale

HDMI-DDC for unknown reasons doesn't work with Exynos I2C controllers.
Fortunately i2c-gpio comes to the rescue.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>