drm/rockchip: inno_hdmi: reorder clk_disable_unprepare call in unbind

In bind the clk_prepare_enable of the HDMI pclk is called before adding the
i2c_adapter. So it should be the other way around in unbind, first remove
the i2c_adapter and then call the clk_disable_unprepare.

Fixes: 412d4ae6 ("drm/rockchip: hdmi: add Innosilicon HDMI support")
Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20180302175757.28192-4-enric.balletbo@collabora.com