Remove opt-out of blocking swap buffers logic for KMSDRM

We don't set SDL_HINT_VIDEO_DOUBLE_BUFFER since b1c77ff.

app/streaming/video/ffmpeg-renderers/eglvid.cpp

@@ -600,17 +600,7 @@ bool EGLRenderer::initialize(PDECODER_PARAMETERS params)
 #endif
             ) {
         SDL_GL_SetSwapInterval(1);
-
-#if SDL_VERSION_ATLEAST(2, 0, 15) && defined(SDL_VIDEO_DRIVER_KMSDRM)
-        // The SDL KMSDRM backend already enforces double buffering (due to
-        // SDL_HINT_VIDEO_DOUBLE_BUFFER=1), so calling glFinish() after
-        // SDL_GL_SwapWindow() will block an extra frame and lock rendering
-        // at 1/2 the display refresh rate.
-        if (info.subsystem != SDL_SYSWM_KMSDRM)
-#endif
-        {
         m_BlockingSwapBuffers = true;
-        }
     } else {
         SDL_GL_SetSwapInterval(0);
     }