ci/win32: override link args only for the target that needs them

Fixes compilation after USE_GAS related fixes upstream. It links
asm_offset.exe, which shouldn't use a .def file.

Fixes: 0125d35

ci/build-win32.ps1

@@ -112,7 +112,7 @@ opts.add_cmake_defines({
  'UPDATE_DEPS': 'ON',
  'USE_GAS': 'ON',
 })
-opts.append_link_args(['-lcfgmgr32', '-Wl,/def:../subprojects/vulkan-loader/loader/vulkan-1.def'])
+opts.append_link_args(['-lcfgmgr32', '-Wl,/def:../subprojects/vulkan-loader/loader/vulkan-1.def'], target: 'vulkan')
 vulkan_proj = cmake.subproject('vulkan-loader', options: opts)
 vulkan_dep = vulkan_proj.dependency('vulkan')
 meson.override_dependency('vulkan', vulkan_dep)