cfg80211/mac80211: Update set_tx_power to use mBm instead of dBm units

In preparation for a TX power setting interface in the nl80211, change the
.set_tx_power function to use mBm units instead of dBm for greater accuracy and
smaller power levels.

Also, already in advance move the tx_power_setting enumeration to nl80211.

This change affects the .tx_set_power function prototype. As a result, the
corresponding changes are needed to modules using it. These are mac80211,
iwmc3200wifi and rndis_wlan.

Cc: Samuel Ortiz <samuel.ortiz@intel.com>
Cc: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Acked-by: Samuel Ortiz <samuel.ortiz@intel.com>
Acked-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/include/linux/nl80211.h b/include/linux/nl80211.h
index 64fb32b..07aa046 100644
--- a/include/linux/nl80211.h
+++ b/include/linux/nl80211.h
@@ -1659,4 +1659,17 @@
 	NL80211_CQM_RSSI_THRESHOLD_EVENT_HIGH,
 };
 
+
+/**
+ * enum nl80211_tx_power_setting - TX power adjustment
+ * @NL80211_TX_POWER_AUTOMATIC: automatically determine transmit power
+ * @NL80211_TX_POWER_LIMITED: limit TX power by the mBm parameter
+ * @NL80211_TX_POWER_FIXED: fix TX power to the mBm parameter
+ */
+enum nl80211_tx_power_setting {
+	NL80211_TX_POWER_AUTOMATIC,
+	NL80211_TX_POWER_LIMITED,
+	NL80211_TX_POWER_FIXED,
+};
+
 #endif /* __LINUX_NL80211_H */