AMD maxImageExtent for surface depends on window size

[zao]

In reports such as my http://vulkan.gpuinfo.org/displayreport.php?id=923#surface, cards like AMD RX 470 list a maxImageExtent of 927x755.

This very odd extent is the same size as the client area of the VulkanCapsViewer HWND, which is used by the code to construct the surface used to query this information.

[SaschaWillems]

Other devices also seem to report the client area of the window instead, so this may be a driver issued

The spec is now 100% clear on this:

maxImageExtent contains the largest valid swapchain extent for the surface on the specified device.

So I may open up an issue to clarify what it actually reports.

[krOoze]

@SaschaWillems The report seems invalid. minImageExtent and maxImageExtent must be equal to currentImageExtent on VK_KHR_win32_surface. I suggest just removing those parameters too from that platform (same applies to Xlib and XCB).