win-capture: Fix bug initializing via d3d9 swap

Apparently neglected to use the reference operator.  I think this may
partially be one of the reasons why many developers still choose to use
pointers instead of references, but fortunately an actual GOOD compiler
warns about this (aka anything but vc)

plugins/win-capture/graphics-hook/d3d9-capture.cpp

@@ -425,7 +425,7 @@ static bool d3d9_init_format_backbuffer(uint32_t &cx, uint32_t &cy,
 	return true;
 }
 
-static bool d3d9_init_format_swapchain(uint32_t cx, uint32_t cy, HWND window)
+static bool d3d9_init_format_swapchain(uint32_t &cx, uint32_t &cy, HWND &window)
 {
 	D3DPRESENT_PARAMETERS pp;