Add ActivateRenderGPU function for dGPU activation

Added a function to activate the render GPU.

Author: Tiflit

src/gpu/gpu_detection.h

@@ -6,6 +6,10 @@
 bool DetectDisplayGPU(GpuState& outState);
 bool DetectRenderGPU(GpuState& outState);
 
+// Creates a dummy D3D11 device to wake/activate the dGPU.
+// Returns true on success.
+bool ActivateRenderGPU();
+
 std::wstring BuildGpuTooltip(
     const GpuState& display,
     const GpuState& render