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/substitute/substitute.sh

@@ -0,0 +1,18 @@
+source $stdenv/setup
+
+args=
+
+target=$out
+if test -n "$dir"; then
+    target=$out/$dir/$name
+    mkdir -p $out/$dir
+fi
+
+substitute $src $target $replacements
+
+if test -n "$isExecutable"; then
+    chmod +x $target
+fi
+
+eval "$postInstall"
+