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/fetchbzr/builder.sh

@@ -0,0 +1,9 @@
+source "$stdenv/setup"
+
+header "exporting \`$url' (revision $rev) into \`$out'"
+
+# Perform a lightweight checkout so that we don't end up importing
+# all the repository's history.
+BZR_LOG=/dev/null bzr -Ossl.cert_reqs=none export -r "$rev" --format=dir "$out" "$url"
+
+stopNest