iter5 sweep: remove iter1 slice_header parse + VAPicture dump + Sync RETURN trace

h264.c:
- Remove the slice_header parse success log (the parse data is now
  forwarded into decode_params directly without per-frame echo). Keep
  the FAILED-rc log since it indicates a real decode-blocking error.
- Remove the iter1 patch-0014 VAPictureH264 byte-dump + field-read
  log block. The TopFieldOrderCnt=65536 anomaly it diagnosed was
  resolved by the POC sentinel strip (h264_strip_ffmpeg_poc_sentinel)
  that stays in the codebase.

surface.c:
- Remove the per-call "RequestSyncSurface RETURN status=" trace.
- Remove the per-call "RequestSyncSurface early-exit" trace.

v4l2.c:
- Suppress the per-frame "Unable to get control(s): Permission denied"
  log when errno == EACCES (the expected case on this hantro rig
  per iter1 patch-0014's findings). The one-time announcement in
  h264.c stays. Real EACCES-on-non-request-fd or other errno values
  still log normally.

Per-frame v4l2-request log noise drops from ~30+ lines/frame to
init-time + once-per-resolution-change.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/v4l2.c

@@ -457,7 +457,16 @@ int v4l2_get_controls(int video_fd, int request_fd,
 	rc = v4l2_ioctl_controls(video_fd, request_fd, VIDIOC_G_EXT_CTRLS,
 				 control_array, num_controls);
 	if (rc < 0) {
-		request_log("Unable to get control(s): %s\n", strerror(errno));
+		/*
+		 * EACCES on G_EXT_CTRLS for request fds is the normal case on
+		 * this hantro rig — the kernel doesn't allow readback through
+		 * the request_fd. Caller (h264.c) tracks this with a one-time
+		 * "V4L2 readback unavailable" announcement. Suppress per-call
+		 * noise to keep the log signal-to-noise high.
+		 */
+		if (errno != EACCES)
+			request_log("Unable to get control(s): %s\n",
+				    strerror(errno));
 		return -1;
 	}