bpf: Remove redundant assignment to meta.seq in __task_seq_show()

The seq argument is assigned to meta.seq twice, the second one is
redundant, remove it.

This patch also removes a redundant space in bpf_iter_link_attach().

Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20220410060020.307283-1-ytcoode@gmail.com