LVDS panels must really be driven at their native resolution, otherwise
they will simply not work. This means we should basically never touch
the video timings on that side. We need to only set the source size in
the pipe configuration, and let the panel fitter figure out the scaling.
On my G45 laptop, this allows me to use non-native resolutions on the
laptop display. This also means when booting with a VGA display
connected, I do get a valid display on the internal panel (using the VGA
resolution). VGA still gets "out of range", so we're still not setting
up something there.
If I switch to VGA display in the BIOS, I get a working picture there
and garbage on the internal display, which is progress (before I would
get a black screen on the internal display)
Fixes#12723.
abcbfac601