drm/sun4i: Add support for A80 TCONs

The Allwinner A80 SoC has 2 documented TCONs. The display pipeline
diagram from the user manual shows a third TCON, but it's missing
an interrupt line, and its registers are not explained either.
It's also not used in Allwinner's vendor BSP.

The first TCON only has channel 0, for LCD panel output. The TCON
hardware setup is peculiar in that the eDP reset must also be
deasserted to allow access to the TCON. How the eDP module is wired
in the SoC itself is never explained.

The second TCON only has channel 1, and its output is connected to
the HDMI encoder block.

This patch adds a "needs_edp_reset" field to the tcon quirks structure,
and adds quirks and compatible strings for the 2 documented TCONs.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180315114136.24747-4-wens@csie.org