vulkan: Fix build on Windows
* Fix meson build script for Windows. Since the Vulkan dependency
object was declared by us in case of Windows, the dependency object
shouldn't be used for finding header
* Fix build error by including Windows specific header
gstvkdisplay.c(563): error C2065: 'VK_KHR_WIN32_SURFACE_EXTENSION_NAME': undeclared identifier
cc: @ystreet