Update the HT operation mode when mac80211 sends it to us and set
the different HT protection modes and rates accordingly. For now
only use CTS-to-self with OFDM 24M or CCK 11M when protection is
required.

Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>