net: sched: fix tcf_block_get_ext() in case CONFIG_NET_CLS is not set

The definition of functions tcf_block_get() and tcf_block_get_ext()
depends of CONFIG_NET_CLS being set. When those functions gained extack
support, only one version of the declaration of those functions was
updated. Function tcf_block_get() was later fixed with commit
3c149091 ("net: sch: api: fix tcf_block_get").

Change arguments of tcf_block_get_ext() for the case when CONFIG_NET_CLS
is not set.

Fixes: 8d1a77f9 ("net: sch: api: add extack support in tcf_block_get")
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>