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>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
diff --git a/doc/README.video b/doc/README.video
index cfe6318..2c55d6a 100644
--- a/doc/README.video
+++ b/doc/README.video
@@ -50,8 +50,7 @@
 
 - hpd=[0|1] - Enable use of the hdmi HotPlug Detect feature
  0: Disabled. Configure dvi/hdmi output even if no cable is detected
- 1: Enabled. If a LCD has been configured fallback to the LCD when no cable is
-    detected, if no LCD is configured, disable video ouput.
+ 1: Enabled.  Fallback to the lcd / vga / none in that order (if available)
  Defaults to hpd=1.
 
 - edid=[0|1] - Enable use of DDC + EDID to get monitor info