drm/i915/vlv: use W_SYNC_SHIFT for interlaced modes on VLV

This makes HDMI testers happier on VLV platforms.  It may be that we
need it for any non-SVO platform, but I don't have any tests to back
that up, so I'm leaving other pre-ILK platforms alone for now.

Tested-by: "Clint Taylor <clinton.a.taylor@intel.com>"
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=74964
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_display.c

@@ -5533,8 +5533,11 @@ static void i9xx_set_pipeconf(struct intel_crtc *intel_crtc)
 		}
 	}
 
-	if (!IS_GEN2(dev) &&
+	if (IS_VALLEYVIEW(dev) &&
 	    intel_crtc->config.adjusted_mode.flags & DRM_MODE_FLAG_INTERLACE)
+		pipeconf |= PIPECONF_INTERLACE_W_SYNC_SHIFT;
+	else if (!IS_GEN2(dev) &&
+		 intel_crtc->config.adjusted_mode.flags & DRM_MODE_FLAG_INTERLACE)
 		pipeconf |= PIPECONF_INTERLACE_W_FIELD_INDICATION;
 	else
 		pipeconf |= PIPECONF_PROGRESSIVE;