libcamera: base: thread: Use std::unique_ptr instead of raw pointer

An `std::unique_ptr` is safer and expresses the intent better, so use that.

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

include/libcamera/base/thread.h

@@ -75,7 +75,7 @@ private:
 			ThreadData *targetData);
 
 	std::thread thread_;
-	ThreadData *data_;
+	std::unique_ptr<ThreadData> data_;
 };
 
 } /* namespace libcamera */