mac80211_hwsim: fix possible memory leak in hwsim_new_radio_nl()

'hwname' is malloced in hwsim_new_radio_nl() and should be freed
before leaving from the error handling cases, otherwise it will cause
memory leak.

Fixes: ff4dd73dd2b4 ("mac80211_hwsim: check HWSIM_ATTR_RADIO_NAME length")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
static void hwsim_mcast_config_msg(struct sk_buff *mcast_skb,
				   struct genl_info *info)
{
	if (info)
		genl_notify(&hwsim_genl_family, mcast_skb, info,
			    HWSIM_MCGRP_CONFIG, GFP_KERNEL);
	else
		genlmsg_multicast(&hwsim_genl_family, mcast_skb, 0,
				  HWSIM_MCGRP_CONFIG, GFP_KERNEL);
}

static void hwsim_mcast_config_msg(struct sk_buff *mcast_skb,
				   struct genl_info *info)
{
	if (info)
		genl_notify(&hwsim_genl_family, mcast_skb, info,
			    HWSIM_MCGRP_CONFIG, GFP_KERNEL);
	else
		genlmsg_multicast(&hwsim_genl_family, mcast_skb, 0,
				  HWSIM_MCGRP_CONFIG, GFP_KERNEL);
}
