drm/i915/dp: Ratelimit DP aux timeout messages

Right now this is just leaving a lot of spam in dmesg that makes real
issues more difficult to debug. As well (as noted by the comment right
above the DRM_DEBUG_KMS() call) this is normal behavior when there's
nothing connected to the DisplayPort connector.
Signed-off-by: Lyude <lyude@redhat.com>

drivers/gpu/drm/i915/intel_dp.c

@@ -1121,7 +1121,8 @@ intel_dp_aux_ch(struct intel_dp *intel_dp,
 	/* Timeouts occur when the device isn't connected, so they're
 	 * "normal" -- don't fill the kernel log with these */
 	if (status & DP_AUX_CH_CTL_TIME_OUT_ERROR) {
-		DRM_DEBUG_KMS("dp_aux_ch timeout status 0x%08x\n", status);
+		DRM_DEBUG_KMS_RATELIMITED("dp_aux_ch timeout status 0x%08x\n",
+					  status);
 		ret = -ETIMEDOUT;
 		goto out;
 	}