chore(tvix): Use callPackage instead of import on Cargo.nix

Since crate2nix v0.11 the new preferred way of importing Cargo.nix is
with callPackage instead of import.

Change-Id: Ifcc5c21e6c101cb9d0b3f1e8025b5ddb8cf99f20
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11855
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
Autosubmit: Ilan Joselevich <personal@ilanjoselevich.com>

tvix/default.nix

@@ -32,10 +32,7 @@ let
     };
 
   # Load the crate2nix crate tree.
-  crates = import ./Cargo.nix {
-    inherit pkgs;
-    nixpkgs = pkgs.path;
-
+  crates = pkgs.callPackage ./Cargo.nix {
     defaultCrateOverrides = pkgs.defaultCrateOverrides // {
       zstd-sys = prev: {
         nativeBuildInputs = prev.nativeBuildInputs or [ ];