nvk: Add missing vk_wsi_args in libnvk's c_args
Without this, NVK will not report VK_KHR_swapchain
support when doing a minimal build.
Example meson setup that show the issue:
meson setup builddir/ -Dprefix="$MESA_INSTALLDIR" -Dgallium-drivers="nouveau" -Dvulkan-drivers="nouveau-experimental" -Dtools="nouveau" -Dbuild-tests=true -Dplatforms=wayland -Dglx=disabled -Degl=disabled -Dgles1=disabled -Dgles2=disabled