tracepoints: Add SPDX headers and copyright notices

Add SPDX headers and copyright notices to the tracepoints definition
files.

Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

include/libcamera/internal/tracepoints/buffer_enums.tp

@@ -1,3 +1,10 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2020, Google Inc.
+ *
+ * buffer_enums.tp - Tracepoint definition for enums in the buffer class
+ */
+
 TRACEPOINT_ENUM(
 	libcamera,
 	buffer_status,

include/libcamera/internal/tracepoints/pipeline.tp

@@ -1,3 +1,10 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2020, Google Inc.
+ *
+ * pipeline.tp - Tracepoints for pipelines
+ */
+
 TRACEPOINT_EVENT(
 	libcamera,
 	ipa_call_begin,

include/libcamera/internal/tracepoints/request.tp

@@ -1,3 +1,10 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2020, Google Inc.
+ *
+ * request.tp - Tracepoints for the request object
+ */
+
 #include <libcamera/buffer.h>
 #include <libcamera/request.h>
 

include/libcamera/internal/tracepoints/request_enums.tp

@@ -1,3 +1,10 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2020, Google Inc.
+ *
+ * request_enums.tp - Tracepoint definition for enums in the request class
+ */
+
 TRACEPOINT_ENUM(
 	libcamera,
 	request_status,