If we touch both files, we can end up in a situation where magic.h should be
rebuilt and isn't. The easiest fix is not to touch the generated files which
ensures the timestamps are such that it is always rebuilt.
(From OE-Core rev: d9519a17ea2ca07433164697a7222dd2b6dd2b9a)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>