DX9: Use D3DCREATE_FPU_PRESERVE as device behavior.

src/renderer_d3d9.cpp

@@ -342,9 +342,9 @@ namespace bgfx
 
 			uint32_t behaviorFlags[] =
 			{
-				D3DCREATE_HARDWARE_VERTEXPROCESSING|D3DCREATE_PUREDEVICE,
-				D3DCREATE_MIXED_VERTEXPROCESSING,
-				D3DCREATE_SOFTWARE_VERTEXPROCESSING,
+				D3DCREATE_HARDWARE_VERTEXPROCESSING|D3DCREATE_PUREDEVICE|D3DCREATE_FPU_PRESERVE,
+				D3DCREATE_MIXED_VERTEXPROCESSING|D3DCREATE_FPU_PRESERVE,
+				D3DCREATE_SOFTWARE_VERTEXPROCESSING|D3DCREATE_FPU_PRESERVE,
 			};
 
 			for (uint32_t ii = 0; ii < BX_COUNTOF(behaviorFlags) && NULL == m_device; ++ii)