drm/i915: Reject odd pipe source width with double wide/dual link

In order to guarantee that pipe_src_w/h matches the user mode h/vdisplay
we must not adjust pipe_src_w to accommodate double wide/dual link.
Instead just reject the mode outright.

This will allows us to rely on crtc_state->mode for plane clipping.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171123190502.28449-2-ville.syrjala@linux.intel.com


Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Thierry Reding <treding@nvidia.com>