the p->parent PID printout gives us all the information about the
task tree that we need - the eldest_child()/older_sibling()/
younger_sibling() printouts are mostly historic and i do not
remember ever having used those fields. (IMO in fact they confuse
the SysRq-T output.) So remove them.

This code has sentimental value though, those fields and
printouts are one of the oldest ones still surviving from
Linux v0.95's kernel/sched.c:

        if (p->p_ysptr || p->p_osptr)
                printk("   Younger sib=%d, older sib=%d\n\r",
                        p->p_ysptr ? p->p_ysptr->pid : -1,
                        p->p_osptr ? p->p_osptr->pid : -1);
        else
                printk("\n\r");

written 15 years ago, in early 1992.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus 'snif' Torvalds <torvalds@linux-foundation.org>