libcamera: rpi: Add missing SPDX headers

Multiple files in the Raspberry Pi pipeline handler and IPA module are
missing SPDX headers. Add them with the following licenses:

- For code and documentation, use the BSD-2-Clause license, as for the
  rest of the Raspberry Pi code.

- For the example pipeline handler configuration files, use the CC0-1.0
  license to facilitate their usage.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Reviewed-by: Naushir Patuck <naush@raspberrypi.com>

src/libcamera/pipeline/rpi/pisp/data/example.yaml

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: CC0-1.0
 {
         "version": 1.0,
         "target": "pisp",

src/libcamera/pipeline/rpi/vc4/data/example.yaml

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: CC0-1.0
 {
         "version": 1.0,
         "target": "bcm2835",