iwinfo: cli: fix hwmode formatting

The placeholder for the 802.11ax hwmode was missing.

Signed-off-by: David Bauer <mail@david-bauer.net>

iwinfo_cli.c

@@ -274,12 +274,12 @@ static char * format_encryption(struct iwinfo_crypto_entry *c)
 
 static char * format_hwmodes(int modes)
 {
-	static char buf[15];
+	static char buf[17];
 
 	if (modes <= 0)
 		snprintf(buf, sizeof(buf), "unknown");
 	else
-		snprintf(buf, sizeof(buf), "802.11%s%s%s%s%s%s",
+		snprintf(buf, sizeof(buf), "802.11%s%s%s%s%s%s%s",
 			(modes & IWINFO_80211_A) ? "a" : "",
 			(modes & IWINFO_80211_B) ? "b" : "",
 			(modes & IWINFO_80211_G) ? "g" : "",