This patch adds support to set transmit power setting type and transmit
power level attributes to NL80211_CMD_SET_STATION in order to facilitate
adjusting the transmit power level of a station associated to the AP.

The added attributes allow selection of automatic and limited transmit
power level, with the level defined in dBm format.
Co-developed-by: NBalaji Pothunoori <bpothuno@codeaurora.org>
Signed-off-by: NAshok Raj Nagarajan <arnagara@codeaurora.org>
Signed-off-by: NBalaji Pothunoori <bpothuno@codeaurora.org>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>