sunxi: A13-OLinuXino defconfigs: Enable VGA output, add lcd-mode for 7" LCD

Enable VGA output on the A13-OLinuXino and A13-OLinuXinoM now that we've
support for it.

Also add LCD timing and gpio info for the Olimex 7" LCD module. We can safely
put this in the default config on this boards, since by default we will always
use VGA, and the LCD timing info will only get used if the user explicitly
sets monitor=lcd in the video-mode env. variable.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>