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>

.github/workflows/no-channel.yml

@@ -0,0 +1,21 @@
+name: "No channel PR"
+
+on:
+  pull_request:
+    branches:
+      - 'nixos-**'
+      - 'nixpkgs-**'
+
+jobs:
+  fail:
+    name: "This PR is is targeting a channel branch"
+    runs-on: ubuntu-latest
+    steps:
+    - run: |
+        cat <<EOF
+        The nixos-* and nixpkgs-* branches are pushed to by the channel
+        release script and should not be merged into directly.
+
+        Please target the equivalent release-* branch or master instead.
+        EOF
+        exit 1