wayland: try to fix display_handle_t type

[Megamouse]

• Use VK_USE_PLATFORM_WAYLAND_KHR instead of HAVE_WAYLAND in gs_frame

maybe fixes #17002

[kd-11]

VK_USE_PLATFORM_WAYLAND_KHR is a hack/workaround coming back to bite us. If you really think about it, as long as we have the right dependencies at compile time, we have no reason to not support both X11 and Wayland. The disambiguation of the handle type is supposed to be done at runtime and is handled. A proper fix should just remove this USE_PLATFORM_WAYLAND_KHR flag completely.

[Megamouse]

The issue on my laptop seems to be that VK_USE_PLATFORM_WAYLAND_KHR is false but HAVE_WAYLAND is true, which leads to this nonsense. Not sure if I can just use HAVE_WAYLAND for the display_handle_t instead without breaking anything. I can maybe test that later.

[kd-11]

Superceded by https://github.com/RPCS3/rpcs3/pull/17120