drm/i915: Disable double wide even when leaving the pipe on

Disable double wide even if the pipe quirk compels us to leave the
pipe running. Double wide has certain implications for the plane
assignments so best keep it off.

Also helps resuming from S3 on the Fujitsu-Siemens Lifebook S6010
when double wide was enabled prior to suspend.

We do leave the pixel clock ticking at the original rate which would
require double wide to be enabled. But since the planes are all disabled
I'm hoping that the overly fast clock won't cause any problems. Seems
to be fine so far.

v2: Disable double wide also when turning the pipe off
v3: Reorder wrt. force pipe B quirk

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: Thomas Richter <richter@rus.uni-stuttgart.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>