uboot: (firmwareOdroidC2/C4) don't invoke patch tool, use patches = [] instead

https://github.com/NixOS/nixpkgs/blob/master/pkgs/stdenv/generic/setup.sh#L948
this can do it nicely.

Signed-off-by: Anton Arapov <anton@deadbeef.mx>

pkgs/tools/nix/info/sandbox.nix

@@ -0,0 +1,10 @@
+let
+  pkgs = import <nixpkgs> {};
+in pkgs.runCommand "diagnostics-sandbox"
+  { }
+  ''
+    set -x
+    # no cache: ${toString builtins.currentTime}
+    test -d "$(dirname "$out")/../var/nix"
+    touch $out
+  ''