bpf, mips: Fix comment on tail call count limiting

In emit_tail_call() of bpf_jit_comp32.c, "blez t2" (t2 <= 0) is
not consistent with the comment "t2 < 0", update the comment to
keep consistency.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Link: https://lore.kernel.org/bpf/1633915150-13220-3-git-send-email-yangtiezhu@loongson.cn