AudioServer: Queue more than 4k bytes per write

Before this I was writing audio data to kernel in ~20 ms chuncks. This
feels like way too many syscalls, so now we allow sending upto 1 second
per syscall :D

userspace/programs/AudioServer/AudioServer.h

@@ -68,7 +68,6 @@ private:
 	size_t m_current_audio_device { 0 };
 
 	size_t m_samples_sent { 0 };
-	BAN::Array<uint8_t, 4 * 1024> m_send_buffer;
 	BAN::CircularQueue<sample_t, 64 * 1024> m_samples;
 
 	BAN::HashMap<int, ClientInfo> m_audio_buffers;