mac80211: set default country to CN

Signed-off-by: Tianling Shen <cnsztl@immortalwrt.org>
(cherry picked from commit a290a61f6d)

package/kernel/mac80211/files/lib/wifi/mac80211.sh

@@ -203,7 +203,7 @@ detect_mac80211() {
 			set wireless.${name}.channel=${channel}
 			set wireless.${name}.band=${mode_band}
 			set wireless.${name}.htmode=$htmode
-			set wireless.${name}.country=US
+			set wireless.${name}.country=CN
 			set wireless.${name}.disabled=0
 
 			set wireless.default_${name}=wifi-iface