sunxi: Add an example defconfig for using the 10" lcd module from olimex

Add an example defconfig for using the 10" lcd module from olimex, this
specific config is for using it in combination with the A20-OLinuXino_MICRO,
but it also serves as an example for how to add support for this lcd module
with other OLinuXino boards.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sunxi: video: Add a hpd_delay parameter to configure hpd delay

In some extreme cases it may be necessary to wait 1.5 seconds or more for a hpd
signal to show up (and be able to read edid info), but we do not want to
penalize all headless boots with an extra second boot delay, so add a hpd_delay
parameter which can be set through the video-mode env. variable.

While at it raise the default from 300ms to 500ms as 300 may very well be too
low in many cases.

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