test: Replace explicit DRM FourCCs with libcamera formats

Use the new pixel format constants to replace usage of macros from
drm_fourcc.h.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

test/v4l2_videodevice/buffer_cache.cpp

@@ -9,6 +9,7 @@
 #include <random>
 #include <vector>
 
+#include <libcamera/formats.h>
 #include <libcamera/stream.h>
 
 #include "buffer_source.h"
@@ -142,7 +143,7 @@ public:
 		const unsigned int numBuffers = 8;
 
 		StreamConfiguration cfg;
-		cfg.pixelFormat = PixelFormat(DRM_FORMAT_YUYV);
+		cfg.pixelFormat = formats::YUYV;
 		cfg.size = Size(600, 800);
 		cfg.bufferCount = numBuffers;