cfg80211: add support for setting the ad-hoc multicast rate

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 5e4dda4..6055538 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -171,6 +171,8 @@
 
 	[NL80211_ATTR_WIPHY_ANTENNA_TX] = { .type = NLA_U32 },
 	[NL80211_ATTR_WIPHY_ANTENNA_RX] = { .type = NLA_U32 },
+
+	[NL80211_ATTR_MCAST_RATE] = { .type = NLA_U32 },
 };
 
 /* policy for the key attributes */
@@ -3681,6 +3683,9 @@
 				return -EINVAL;
 		}
 	}
+	if (info->attrs[NL80211_ATTR_MCAST_RATE])
+		ibss.mcast_rate =
+			nla_get_u32(info->attrs[NL80211_ATTR_MCAST_RATE]);
 
 	if (ibss.privacy && info->attrs[NL80211_ATTR_KEYS]) {
 		connkeys = nl80211_parse_connkeys(rdev,