ARM: sun5i: a10s: Add the HDMI controller node

The A10s has an HDMI controller connected to the second TCON channel. Add
it to our DT.

Since the TV Encoder was the only channel 1 user so far, also add the
property now that we have several users.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
[wens@csie.org: Replaced CLK_PLL_VIDEO[01]_2X with raw numbers for now
Signed-off-by: Chen-Yu Tsai <wens@csie.org>