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/build-support/fetchs3/default.nix

@@ -0,0 +1,36 @@
+{ lib, runCommand, awscli }:
+
+{ s3url
+, name ? builtins.baseNameOf s3url
+, sha256
+, region ? "us-east-1"
+, credentials ? null # Default to looking at local EC2 metadata service
+, recursiveHash ? false
+, postFetch ? null
+}:
+
+let
+  mkCredentials = { access_key_id, secret_access_key, session_token ? null }: {
+    AWS_ACCESS_KEY_ID = access_key_id;
+    AWS_SECRET_ACCESS_KEY = secret_access_key;
+    AWS_SESSION_TOKEN = session_token;
+  };
+
+  credentialAttrs = lib.optionalAttrs (credentials != null) (mkCredentials credentials);
+in runCommand name ({
+  nativeBuildInputs = [ awscli ];
+
+  outputHashAlgo = "sha256";
+  outputHash = sha256;
+  outputHashMode = if recursiveHash then "recursive" else "flat";
+
+  preferLocalBuild = true;
+
+  AWS_DEFAULT_REGION = region;
+} // credentialAttrs) (if postFetch != null then ''
+  downloadedFile="$(mktemp)"
+  aws s3 cp ${s3url} $downloadedFile
+  ${postFetch}
+'' else  ''
+  aws s3 cp ${s3url} $out
+'')