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/camera_sensor.cpp

@@ -5,13 +5,14 @@
  * camera_sensor.cpp - A camera sensor
  */
 
+#include "camera_sensor.h"
+
 #include <algorithm>
 #include <float.h>
 #include <iomanip>
 #include <limits.h>
 #include <math.h>
 
-#include "camera_sensor.h"
 #include "formats.h"
 #include "v4l2_subdevice.h"