The bit doesn't stick, and the output is always cloned from pipe A,
even when it's supposed to scan out from pipe B.

Shuts up annoying warnings from the modeset-rework, too.

I've noticed that with this patch we know get and unknown connection
state since the code can't find a suitable pipe for load detection.
But that beats the previous state of affairs, where it tried to use
pipe B, actually used pipe A and concluded that something is connected
(although it's the LVDS on pipe A and nothing on the VGA connector on
pipe B).

I've tried to make load detect work by remapping the pipe->planes
stuff, so that crtc 0 will use pipe B and hence we still have
something left for load-detect on pipe A. But alas, that upset the hw
a bit.

So there's still some things to figure out, but this here will at
least paper over some of the problems.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=51265


Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
[danvet: extend the commit message a bit with recent observations.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>