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/fetchhg/builder.sh

@@ -0,0 +1,9 @@
+source $stdenv/setup
+header "getting $url${rev:+ ($rev)} into $out"
+
+hg clone --insecure "$url" hg-clone
+
+hg archive -q$subrepoClause -y ${rev:+-r "$rev"} --cwd hg-clone $out
+rm -f $out/.hg_archival.txt
+
+stopNest