sunxi: video: Fix tcon0 hsync / vsync setting

It turns out that the problems I was seeing were due to a bad powersupply,
so enable proper negative hsync / vsync support.

Also adjust various defconfigs to keep the hsync and vsync for the lcd
panels positive, changing sync:0 into sync:3.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sunxi: video: Add support for using PORTD hsync/vsync pins with tcon1

Add support for using PORTD hsync/vsync pins with tcon1, this is a preparation
patch for adding native VGA support.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sunxi: video: Fallback from HDMI to VGA on boards with VGA

If a board has no LCD, but does have VGA fallback to VGA when no HDMI cable
is connected (unless hpd=0).

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sunxi: video: Add VGA output support

Add support for VGA directly from the sunxi SoC / display engine.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>