drm/i915: Tune down WARN about incorrect VBT TC legacy flag

Looks like VBT contains again the wrong information about a port's TypeC
legacy vs. DP-alt/TBT-alt type. There is no further issues after we
notice this and fix it up, so tune down the WARN to be a a DRM_ERROR.

This also avoids CI tainting the kernel and stopping the test run.

v2:
- Update also code coment accordingly. (Jani)

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110578
Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190502101754.29219-1-imre.deak@intel.com

drivers/gpu/drm/i915/intel_dp.c

@@ -5227,12 +5227,15 @@ static bool icl_tc_port_connected(struct drm_i915_private *dev_priv,
 	u32 dpsp;
 
 	/*
-	 * WARN if we got a legacy port HPD, but VBT didn't mark the port as
+	 * Complain if we got a legacy port HPD, but VBT didn't mark the port as
 	 * legacy. Treat the port as legacy from now on.
 	 */
-	if (WARN_ON(!intel_dig_port->tc_legacy_port &&
-		    I915_READ(SDEISR) & SDE_TC_HOTPLUG_ICP(tc_port)))
+	if (!intel_dig_port->tc_legacy_port &&
+	    I915_READ(SDEISR) & SDE_TC_HOTPLUG_ICP(tc_port)) {
+		DRM_ERROR("VBT incorrectly claims port %c is not TypeC legacy\n",
+			  port_name(port));
 		intel_dig_port->tc_legacy_port = true;
+	}
 	is_legacy = intel_dig_port->tc_legacy_port;
 
 	/*