clk: sunxi-ng: sun6i: Fix enable bit offset for hdmi-ddc module clock

The enable bit offset for the hdmi-ddc module clock is wrong. It is
pointing to the main hdmi module clock enable bit.

Reported-by: Bob Ham <rah@settrans.net>
Fixes: c6e6c96d ("clk: sunxi-ng: Add A31/A31s clocks")
Cc: stable@vger.kernel.org # 4.9.x-
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>