xrRender: fix field overflow

Author: eagleivg

src/Layers/xrRender/HWCaps.cpp

@@ -238,7 +238,7 @@ void CHWCaps::Update()
     // ***************** PIXEL processing
     raster_major = 4;
     raster_minor = 0;
-    raster.dwStages = 16;
+    raster.dwStages = 15;
     raster.bNonPow2 = TRUE;
     raster.bCubemap = TRUE;
     raster.dwMRT_count = 4;