libobs: Do not hide OBS_NIX_PLATFORM_WAYLAND behind ifdef

Really no reason to make it so this value can't be used.

Fixes obsproject/obs-studio#9454

libobs/obs-nix-platform.h

@@ -26,10 +26,7 @@ extern "C" {
 enum obs_nix_platform_type {
 	OBS_NIX_PLATFORM_X11_GLX OBS_DEPRECATED,
 	OBS_NIX_PLATFORM_X11_EGL,
-#ifdef ENABLE_WAYLAND
 	OBS_NIX_PLATFORM_WAYLAND,
-#endif
-
 };
 
 /**