libcamera: Include header related to source file first

Include the header file corresponding to the source file in the very
first position. This complies with the Google C++ coding style
guideliens, and helps ensuring that the headers are self-contained.

Three bugs are already caught by this change (missing includes or
forward declarations) in device_enumerator.h, event_dispatcher_poll.h
and pipeline_handler.h. Fix them.

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

src/libcamera/media_device.cpp

@@ -5,6 +5,8 @@
  * media_device.cpp - Media device handler
  */
 
+#include "media_device.h"
+
 #include <errno.h>
 #include <fcntl.h>
 #include <string.h>
@@ -17,7 +19,6 @@
 #include <linux/media.h>
 
 #include "log.h"
-#include "media_device.h"
 
 /**
  * \file media_device.h