mac80211_hwsim: Send alpha2 only if non-zero

A properly set alpha2 value consists of two chars that both contain
letters or digits. If no value is set, both chars keep their initial
value zero. Therefore do not send the alpha2 parameter to user space
if either of the characters has been left at its initial zero value.
Signed-off-by: Patrik Flykt <patrik.flykt@linux.intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/mac80211_hwsim.c

@@ -2541,7 +2541,9 @@ static int mac80211_hwsim_get_radio(struct sk_buff *skb,
 	if (cb)
 		genl_dump_check_consistent(cb, hdr, &hwsim_genl_family);
 
-	param.reg_alpha2 = data->alpha2;
+	if (data->alpha2[0] && data->alpha2[1])
+		param.reg_alpha2 = data->alpha2;
+
 	param.reg_strict = !!(data->hw->wiphy->regulatory_flags &
 					REGULATORY_STRICT_REG);
 	param.p2p_device = !!(data->hw->wiphy->interface_modes &