nl80211: Add new WIPHY attribute COVERAGE_CLASS

The new attribute NL80211_ATTR_WIPHY_COVERAGE_CLASS sets IEEE 802.11
Coverage Class, which depends on maximum distance of nodes in a
wireless network. It's required for long distance links (more than a few
hundred meters).

The attribute is now ignored by two non-mac80211 drivers, rndis and
iwmc3200wifi, together with WIPHY_PARAM_RETRY_SHORT and
WIPHY_PARAM_RETRY_LONG. If it turns out to be a problem, we could split
set_wiphy_params callback or add new capability bits.

Signed-off-by: Lukas Turek <8an@praha12.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index add7993..a8d5d04 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -837,6 +837,7 @@
 	WIPHY_PARAM_RETRY_LONG		= 1 << 1,
 	WIPHY_PARAM_FRAG_THRESHOLD	= 1 << 2,
 	WIPHY_PARAM_RTS_THRESHOLD	= 1 << 3,
+	WIPHY_PARAM_COVERAGE_CLASS	= 1 << 4,
 };
 
 /**
@@ -1236,6 +1237,7 @@
 	u8 retry_long;
 	u32 frag_threshold;
 	u32 rts_threshold;
+	u8 coverage_class;
 
 	char fw_version[ETHTOOL_BUSINFO_LEN];
 	u32 hw_version;