Remove handling for Windows versions that are no longer supported

app/streaming/video/ffmpeg-renderers/d3d11va.cpp

@@ -10,7 +10,6 @@
 #include "streaming/session.h"
 
 #include <SDL_syswm.h>
-#include <VersionHelpers.h>
 
 #include <dwmapi.h>
 
@@ -465,13 +464,6 @@ bool D3D11VARenderer::initialize(PDECODER_PARAMETERS params)
                     "D3D11VA is disabled by environment variable");
         return false;
     }
-    else if (!IsWindows10OrGreater()) {
-        // Use DXVA2 on anything older than Win10, so we don't have to handle a bunch
-        // of legacy Win7/Win8 codepaths in here.
-        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
-                     "D3D11VA renderer is only supported on Windows 10 or later.");
-        return false;
-    }
 
     if (!SDL_DXGIGetOutputInfo(SDL_GetWindowDisplayIndex(params->window),
                                &m_AdapterIndex, &outputIndex)) {

app/streaming/video/ffmpeg-renderers/dxva2.cpp

@@ -18,7 +18,6 @@ extern "C" {
 
 #define WIN32_LEAN_AND_MEAN
 #include <Windows.h>
-#include <VersionHelpers.h>
 #include <dwmapi.h>
 
 #include <Limelight.h>

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

@@ -4,7 +4,6 @@
 #ifdef Q_OS_WIN32
 #define WIN32_LEAN_AND_MEAN
 #include <Windows.h>
-#include <VersionHelpers.h>
 #include "dxvsyncsource.h"
 #endif
 
@@ -283,11 +282,7 @@ bool Pacer::initialize(SDL_Window* window, int maxVideoFps, bool enablePacing)
         switch (info.subsystem) {
     #ifdef Q_OS_WIN32
         case SDL_SYSWM_WINDOWS:
-            // Don't use D3DKMTWaitForVerticalBlankEvent() on Windows 7, because
-            // it blocks during other concurrent DX operations (like actually rendering).
-            if (IsWindows8OrGreater()) {
-                m_VsyncSource = new DxVsyncSource(this);
-            }
+            m_VsyncSource = new DxVsyncSource(this);
             break;
     #endif