cross.nix: move to subdir

hosts/common/cross/default.nix

@@ -83,8 +83,8 @@ let
   # these are the overlays which we *also* pass through to the cross and emulated package sets.
   # TODO: refactor to not specify same overlay in multiple places (here and flake.nix).
   overlays = [
-    (import ./../../overlays/pkgs.nix)
-    (import ./../../overlays/pins.nix)
+    (import ./../../../overlays/pkgs.nix)
+    (import ./../../../overlays/pins.nix)
   ];
   mkCrossFrom = localSystem: pkgs:
     import pkgs.path {

hosts/common/default.nix

@@ -1,7 +1,7 @@
 { lib, pkgs, ... }:
 {
   imports = [
-    ./cross.nix
+    ./cross
     ./feeds.nix
     ./fs.nix
     ./hardware.nix