nfc: Ensure presence of required attributes in the deactivate_target handler

Check that the NFC_ATTR_TARGET_INDEX attributes (in addition to
NFC_ATTR_DEVICE_INDEX) are provided by the netlink client prior to
accessing them. This prevents potential unhandled NULL pointer dereference
exceptions which can be triggered by malicious user-mode programs,
if they omit one or both of these attributes.

Signed-off-by: Young Xiao <92siuyang@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
void nfc_genl_data_init(struct nfc_genl_data *genl_data)
{
	genl_data->poll_req_portid = 0;
	mutex_init(&genl_data->genl_data_mutex);
}

void nfc_genl_data_init(struct nfc_genl_data *genl_data)
{
	genl_data->poll_req_portid = 0;
	mutex_init(&genl_data->genl_data_mutex);
}
