drm/i915: TVDAC_STATE_CHG does not indicate successful load-detect

Do not use this bit to indicate that load detection has completed,
instead just wait for vblank, at which point the load registers will
have been updated.
Signed-off-by: Keith Packard <keithp@keithp.com>
Tested-by: Yi Sun <yi.sun@intel.com>

drivers/gpu/drm/i915/intel_tv.c

@@ -1283,7 +1283,7 @@ intel_tv_detect_type (struct intel_tv *intel_tv,
 			      to_intel_crtc(intel_tv->base.base.crtc)->pipe);
 
 	type = -1;
-	if (wait_for((tv_dac = I915_READ(TV_DAC)) & TVDAC_STATE_CHG, 20) == 0) {
+	tv_dac = I915_READ(TV_DAC);
 	DRM_DEBUG_KMS("TV detected: %x, %x\n", tv_ctl, tv_dac);
 	/*
 	 *  A B C
@@ -1302,7 +1302,7 @@ intel_tv_detect_type (struct intel_tv *intel_tv,
 		type = DRM_MODE_CONNECTOR_Component;
 	} else {
 		DRM_DEBUG_KMS("Unrecognised TV connection\n");
-		}
+		type = -1;
 	}
 
 	I915_WRITE(TV_DAC, save_tv_dac & ~TVDAC_STATE_CHG_EN);