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>

nixos/lib/make-channel.nix

@@ -0,0 +1,31 @@
+/* Build a channel tarball. These contain, in addition to the nixpkgs
+ * expressions themselves, files that indicate the version of nixpkgs
+ * that they represent.
+ */
+{ pkgs, nixpkgs, version, versionSuffix }:
+
+pkgs.releaseTools.makeSourceTarball {
+  name = "nixos-channel";
+
+  src = nixpkgs;
+
+  officialRelease = false; # FIXME: fix this in makeSourceTarball
+  inherit version versionSuffix;
+
+  buildInputs = [ pkgs.nix ];
+
+  distPhase = ''
+    rm -rf .git
+    echo -n $VERSION_SUFFIX > .version-suffix
+    echo -n ${nixpkgs.rev or nixpkgs.shortRev} > .git-revision
+    releaseName=nixos-$VERSION$VERSION_SUFFIX
+    mkdir -p $out/tarballs
+    cp -prd . ../$releaseName
+    chmod -R u+w ../$releaseName
+    ln -s . ../$releaseName/nixpkgs # hack to make ‘<nixpkgs>’ work
+    NIX_STATE_DIR=$TMPDIR nix-env -f ../$releaseName/default.nix -qaP --meta --xml \* > /dev/null
+    cd ..
+    chmod -R u+w $releaseName
+    tar cfJ $out/tarballs/$releaseName.tar.xz $releaseName
+  '';
+}