carl9170 firmware: add radar pattern generator

This - rather large - patch includes parts of a
future radar pattern generator which hopefully
can be used for testing DFS without having to
resort to expensive hardware.

The basic concept has been successfully tested with
p54 [firmware detector - easy to fool] . But, that
does not mean it works with other devices just as
well (or at all!).

Note: This feature is WIP and it will not work
out-of-the-box.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>