drm/i915/dp: Tune down FEC detection timeout error message

At least a Realtek DP branch device with the

OUI 00-e0-4c dev-ID Dp1.4 HW-rev 1.0 SW-rev 131.1

device identification doesn't report detecting the FEC decoding start
symbol. Tune down the corresponding error to a debug message.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231113142051.258864-1-imre.deak@intel.com

drivers/gpu/drm/i915/display/intel_ddi.c

@@ -2257,8 +2257,8 @@ static void wait_for_fec_detected(struct drm_dp_aux *aux, bool enabled)
 		return;
 
 	if (err == -ETIMEDOUT)
-		drm_err(&i915->drm, "Timeout waiting for FEC %s to get detected\n",
-			str_enabled_disabled(enabled));
+		drm_dbg_kms(&i915->drm, "Timeout waiting for FEC %s to get detected\n",
+			    str_enabled_disabled(enabled));
 	else
 		drm_dbg_kms(&i915->drm, "FEC detected status read error: %d\n", status);
 }