kern-tools: include utility to post process config diffs

kern-tools: include utility to post process config diffs

Trevor Woerner contributed a simple utility that cleans up a .config
diff to produce a fragment.

    kconfig-diff2frag.py: introduce a utility to post process a config diff

    Add a python tool to generate a config fragment from a unified diff of two
    kernel configurations. The diff is read from stdin and the fragment is printed
    to stdout.

    Usage:
            $ diff -u config1 config2 | kconfig-diff2frag.py

Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>