cls_api: add flow_indr_block_call function

This patch make indr_block_call don't access struct tc_indr_block_cb
and tc_indr_block_dev directly

Signed-off-by: wenxu <wenxu@ucloud.cn>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>