drm/i915/sdvo: Fully translate sync flags in the dtd->mode conversion

Instead of just a flag bit for each of the positive/negative sync
modes drm actually uses a separate flag for each ... This upsets the
modeset checker since the adjusted mode filled out at modeset time
doesn't match the one reconstructed at check time (since the
->get_config callback already gets this right).
Reported-by: NKnut Petersen <Knut_Petersen@t-online.de>
Cc: Knut Petersen <Knut_Petersen@t-online.de>
References: http://www.gossamer-threads.com/lists/linux/kernel/1778688?do=post_view_threadedReviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_sdvo.c

@@ -866,8 +866,12 @@ static void intel_sdvo_get_mode_from_dtd(struct drm_display_mode * mode,
 		mode->flags |= DRM_MODE_FLAG_INTERLACE;
 	if (dtd->part2.dtd_flags & DTD_FLAG_HSYNC_POSITIVE)
 		mode->flags |= DRM_MODE_FLAG_PHSYNC;
+	else
+		mode->flags |= DRM_MODE_FLAG_NHSYNC;
 	if (dtd->part2.dtd_flags & DTD_FLAG_VSYNC_POSITIVE)
 		mode->flags |= DRM_MODE_FLAG_PVSYNC;
+	else
+		mode->flags |= DRM_MODE_FLAG_NVSYNC;
 }
 
 static bool intel_sdvo_check_supp_encode(struct intel_sdvo *intel_sdvo)