wiphy: Remove unneeded check

The wiphy attribute should never be repeated by the kernel, so this
check is ultimately not needed.  This condition can also be easily
checked by looking at the iwmon output in case things do go terribly
wrong.

src/wiphy.c

@@ -298,9 +298,6 @@ static void wiphy_parse_attributes(struct wiphy *wiphy,
 
 	while (l_genl_attr_next(attr, &type, &len, &data)) {
 		switch (type) {
-		case NL80211_ATTR_WIPHY:
-			l_warn("Duplicate wiphy attribute");
-			break;
 		case NL80211_ATTR_WIPHY_NAME:
 			if (len > sizeof(wiphy->name))
 				l_warn("Invalid wiphy name attribute");