android: Convert to pragma once

Remove the verbose #ifndef/#define/#endif pattern for maintaining
header idempotency, and replace it with a simple #pragma once.

This simplifies the headers, and prevents redundant changes when
header files get moved.

Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>

src/android/camera_request.h

@@ -4,8 +4,8 @@
  *
  * camera_request.h - libcamera Android Camera Request Descriptor
  */
-#ifndef __ANDROID_CAMERA_REQUEST_H__
-#define __ANDROID_CAMERA_REQUEST_H__
+
+#pragma once
 
 #include <map>
 #include <memory>
@@ -80,5 +80,3 @@ public:
 private:
 	LIBCAMERA_DISABLE_COPY(Camera3RequestDescriptor)
 };
-
-#endif /* __ANDROID_CAMERA_REQUEST_H__ */