libcamera: Remove space between empty curly brackets

Remove spaces between empty curly brackets (replacing { } with {}) to
comply with the coding style. Fix one other coding style violation on
the lines touched by those fixes.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

src/libcamera/message.cpp

@@ -93,7 +93,7 @@ Message::~Message()
  * class MyCustomMessage : public Message
  * {
  * public:
- *	MyCustomMessage() : Message(type()) { }
+ *	MyCustomMessage() : Message(type()) {}
  *
  *	static Message::Type type()
  *	{