MIPS: DTS: CI20: Add DT nodes for HDMI setup

We need to hook up
* HDMI connector
* HDMI power regulator
* JZ4780_CLK_HDMI @ 27 MHz
* DDC pinmux
* HDMI and LCDC endpoint connections

Signed-off-by: Paul Boddie <paul@boddie.org.uk>
Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>