libcamera: base: log: Remove LogMessage::init()

It is a short function that can be merged into the constructor with
essentially no change in observable behaviour, so do that.

Signed-off-by: Barnabás Pőcze <pobrn@protonmail.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>

include/libcamera/base/log.h

@@ -75,8 +75,6 @@ public:
 private:
 	LIBCAMERA_DISABLE_COPY_AND_MOVE(LogMessage)
 
-	void init(const char *fileName, unsigned int line);
-
 	std::ostringstream msgStream_;
 	const LogCategory &category_;
 	LogSeverity severity_;