wine-{staging,wayland}: Simplify definitions

These are actually just mere aliases for things we already have, so let'
redefine them more simply accordingly.

Not moving to `aliases.nix` yet because that is a separate policy
decision, and I want to backport this.

pkgs/top-level/all-packages.nix

@@ -12880,17 +12880,9 @@ with pkgs;
   wine = winePackages.full;
   wine64 = wine64Packages.full;
 
-  wine-staging = lowPrio (
-    winePackages.full.override {
-      wineRelease = "staging";
-    }
-  );
+  wine-staging = lowPrio winePackages.stagingFull;
 
-  wine-wayland = lowPrio (
-    winePackages.full.override {
-      x11Support = false;
-    }
-  );
+  wine-wayland = lowPrio winePackages.waylandFull;
 
   inherit (callPackage ../servers/web-apps/wordpress { })
     wordpress