Add TX power per-rate tables for different MIMO modes (e.g STBC) in order to
cap the maximum TX power value per-rate in the TX descriptor path.
Cap TX power for self generated frames (ACK, RTS/CTS).
Currently TPC is supported just by AR9003 based chips
Signed-off-by: NLorenzo Bianconi <lorenzo.bianconi83@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>