pkt_sched: fix error return code in fw_change_attrs()

Fix to return -EINVAL when tb[TCA_FW_MASK] is set and head->mask != 0xFFFFFFFF
instead of 0 (ifdef CONFIG_NET_CLS_IND and tb[TCA_FW_INDEV]), as done elsewhere
in this function.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>