libcamera: Define a PixelFormat type for application-facing formats

Define a PixelFormat type as a simple typedef to an uint32_t. The usage
of a dedicated type creates a cleaner and more self-described API.

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

include/libcamera/meson.build

@@ -9,6 +9,7 @@ libcamera_api = files([
     'geometry.h',
     'logging.h',
     'object.h',
+    'pixelformats.h',
     'request.h',
     'signal.h',
     'stream.h',