drm/i915/tv: After disabling the pipe, use wait_for_vblank_off()

Hopefully this is a contributing factor to the spurious TV detection
repoted by Ivan Bulatovic and others.

References:

  Bug 16871 - "TV1 connected" with no tv
  https://bugzilla.kernel.org/show_bug.cgi?id=16871

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reported-by: Ivan Bulatovic <combuster@gmx.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>

drivers/gpu/drm/i915/intel_tv.c

@@ -1164,7 +1164,7 @@ intel_tv_mode_set(struct drm_encoder *encoder, struct drm_display_mode *mode,
 
 		I915_WRITE(pipeconf_reg, pipeconf & ~PIPEACONF_ENABLE);
 		/* Wait for vblank for the disable to take effect. */
-		intel_wait_for_vblank(dev, intel_crtc->pipe);
+		intel_wait_for_vblank_off(dev, intel_crtc->pipe);
 
 		/* Filter ctl must be set before TV_WIN_SIZE */
 		I915_WRITE(TV_FILTER_CTL_1, TV_AUTO_SCALE);