libcamera: Add missing SPDX headers for miscellaneous CC0-1.0 contents

Miscellaneous files that are not considered copyrightable are missing an
SPDX-License-Identifier header. Fix this by adding a header listing the
CC0-1.0 license.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>

subprojects/pybind11.wrap

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: CC0-1.0
+
 [wrap-git]
 url = https://github.com/pybind/pybind11.git
 # This is the head of 'smart_holder' branch