Rework Nvdec and VIC to fix out-of-order videos, and speed up decoding.

src/video_core/gpu.h

@@ -234,15 +234,6 @@ public:
     /// Push GPU command entries to be processed
     void PushGPUEntries(s32 channel, Tegra::CommandList&& entries);
 
-    /// Push GPU command buffer entries to be processed
-    void PushCommandBuffer(u32 id, Tegra::ChCommandHeaderList& entries);
-
-    /// Frees the CDMAPusher instance to free up resources
-    void ClearCdmaInstance(u32 id);
-
-    /// Swap buffers (render frame)
-    void SwapBuffers(const Tegra::FramebufferConfig* framebuffer);
-
     /// Notify rasterizer that any caches of the specified region should be flushed to Switch memory
     [[nodiscard]] VideoCore::RasterizerDownloadArea OnCPURead(DAddr addr, u64 size);