flake: set nix-xillinx to not follow nixpkgs

flake.lock

@@ -73,9 +73,7 @@
     "nix-xilinx": {
       "inputs": {
         "flake-compat": "flake-compat",
-        "nixpkgs": [
-          "nixpkgs"
-        ]
+        "nixpkgs": "nixpkgs"
       },
       "locked": {
         "lastModified": 1685780173,
@@ -93,18 +91,16 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1695830400,
-        "narHash": "sha256-gToZXQVr0G/1WriO83olnqrLSHF2Jb8BPcmCt497ro0=",
-        "owner": "nixos",
+        "lastModified": 1695806987,
+        "narHash": "sha256-fX5kGs66NZIxCMcpAGIpxuftajHL8Hil1vjHmjjl118=",
+        "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "8a86b98f0ba1c405358f1b71ff8b5e1d317f5db2",
+        "rev": "f3dab3509afca932f3f4fd0908957709bb1c1f57",
         "type": "github"
       },
       "original": {
-        "owner": "nixos",
-        "ref": "nixos-unstable",
-        "repo": "nixpkgs",
-        "type": "github"
+        "id": "nixpkgs",
+        "type": "indirect"
       }
     },
     "nixpkgs-stable": {
@@ -123,6 +119,22 @@
         "type": "github"
       }
     },
+    "nixpkgs_2": {
+      "locked": {
+        "lastModified": 1695830400,
+        "narHash": "sha256-gToZXQVr0G/1WriO83olnqrLSHF2Jb8BPcmCt497ro0=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "8a86b98f0ba1c405358f1b71ff8b5e1d317f5db2",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "peerix": {
       "inputs": {
         "flake-compat": "flake-compat_2",
@@ -149,7 +161,7 @@
       "inputs": {
         "home-manager": "home-manager",
         "nix-xilinx": "nix-xilinx",
-        "nixpkgs": "nixpkgs",
+        "nixpkgs": "nixpkgs_2",
         "peerix": "peerix",
         "sops-nix": "sops-nix",
         "zremap": "zremap"