nl80211: add Guard Interval support for set_bitrate_mask

Allow to force SGI, LGI.
Mainly for test purpose.

Signed-off-by: Janusz Dziedzic <janusz.dziedzic@tieto.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 09b6da8..a3515eb 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -7447,6 +7447,7 @@
 	[NL80211_TXRATE_HT] = { .type = NLA_BINARY,
 				.len = NL80211_MAX_SUPP_HT_RATES },
 	[NL80211_TXRATE_VHT] = { .len = sizeof(struct nl80211_txrate_vht)},
+	[NL80211_TXRATE_GI] = { .type = NLA_U8 },
 };
 
 static int nl80211_set_tx_bitrate_mask(struct sk_buff *skb,
@@ -7527,6 +7528,12 @@
 					mask.control[band].vht_mcs))
 				return -EINVAL;
 		}
+		if (tb[NL80211_TXRATE_GI]) {
+			mask.control[band].gi =
+				nla_get_u8(tb[NL80211_TXRATE_GI]);
+			if (mask.control[band].gi > NL80211_TXRATE_FORCE_LGI)
+				return -EINVAL;
+		}
 
 		if (mask.control[band].legacy == 0) {
 			/* don't allow empty legacy rates if HT or VHT