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/os-specific/linux/kernel/update-zen.sh

@@ -0,0 +1,23 @@
+#! /usr/bin/env nix-shell
+#! nix-shell -I nixpkgs=../../../.. -i bash -p nix-prefetch git gnused gnugrep nix curl
+set -euo pipefail -x
+
+nixpkgs="$(git rev-parse --show-toplevel)"
+old=$(nix-instantiate --eval -A linuxPackages_zen.kernel.modDirVersion "$nixpkgs")
+old="${old%\"}"
+old="${old#\"}"
+new=$(curl https://github.com/zen-kernel/zen-kernel/releases.atom | grep -m1 -o -E '[0-9.]+-zen[0-9]+')
+# add ".0" patch to modDirVersion when minor only
+new=$(echo "$new" | sed -E 's/^([0-9]+)\.([0-9]+)-(\w+)$/\1.\2.0-\3/')
+if [[ "$new" == "$old" ]]; then
+    echo "already up-to-date"
+    exit 0
+fi
+
+path="$nixpkgs/pkgs/os-specific/linux/kernel/linux-zen.nix"
+
+sed -i -e "s!modDirVersion = \".*\"!modDirVersion = \"${new}\"!" "$path"
+checksum=$(nix-prefetch "(import ${nixpkgs} {}).linuxPackages_zen.kernel")
+sed -i -e "s!sha256 = \".*\"!sha256 = \"${checksum}\"!" "$path"
+
+git commit -m "linuxKernel.kernels.linux_zen: ${old} -> ${new}" $path