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/rfkill/rfkill-hook.sh

@@ -0,0 +1,19 @@
+#!@shell@
+
+# Executes a hook in case of a change to the
+# rfkill state. The hook can be passed as
+# environment variable, or present as executable
+# file.
+
+if [ -z "$RFKILL_STATE" ]; then
+  echo "rfkill-hook: error: RFKILL_STATE variable not set"
+  exit 1
+fi
+
+if [ -x /run/current-system/etc/rfkill.hook ]; then
+  exec /run/current-system/etc/rfkill.hook
+elif [ ! -z "$RFKILL_HOOK" ]; then
+  exec $RFKILL_HOOK
+else
+  echo "rfkill-hook: $RFKILL_STATE"
+fi