clk: sunxi: Add TCON channel1 clock

The TCON is a controller generating the timings to output videos signals,
acting like both a CRTC and an encoder.

It has two channels depending on the output, each channel being driven by
its own clock (and own clock controller).

Add a driver for the channel 1 clock.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Stephen Boyd <sboyd@codeaurora.org>