Try Vulkan if CUDA is not available

src/video_core/host1x/ffmpeg/ffmpeg.cpp

@@ -28,16 +28,19 @@ constexpr AVPixelFormat PreferredCpuFormat = AV_PIX_FMT_YUV420P;
 constexpr std::array PreferredGpuDecoders = {
 #if defined(_WIN32)
     AV_HWDEVICE_TYPE_CUDA,
+    AV_HWDEVICE_TYPE_VULKAN,
     AV_HWDEVICE_TYPE_D3D11VA,
     AV_HWDEVICE_TYPE_DXVA2,
 #elif defined(__FreeBSD__)
     AV_HWDEVICE_TYPE_VDPAU,
-#elif defined(__unix__)
+#elif defined(__linux__)
     AV_HWDEVICE_TYPE_CUDA,
+    AV_HWDEVICE_TYPE_VULKAN,
     AV_HWDEVICE_TYPE_VAAPI,
     AV_HWDEVICE_TYPE_VDPAU,
-#endif
+#else
     AV_HWDEVICE_TYPE_VULKAN,
+#endif
 };
 
 AVPixelFormat GetGpuFormat(AVCodecContext* codec_context, const AVPixelFormat* pix_fmts) {