[Crash-utility] fix bug of struct command

[Dave Anderson]

----- Original Message -----
> Hello Dave,
> 
> The attachment is used to fix a bug of struct command.
> 
> When using command like below, struct command displays wrong data.
> 
> <cut>
> crash> task_struct.fs ffff88003dfb5540
>     fs = 140234226652928
> crash> task_struct ffff88003dfb5540
> ...
>     es = 0,
>     ds = 0,
>     fsindex = 0,
>     gsindex = 0,
>     *fs = 140234226652928,*
>     gs = 0,
>     debugreg0 = 0,
> ...
>     io_bitmap_ptr = 0x0,
>     iopl = 0,
>     io_bitmap_max = 0
>   },
>   *fs = 0xffff880037795f00,*
>   files = 0xffff8800371b6940,
> ...
> <cut>
> 
> fs showed by struct command is a member of "struct thread_struct thread;",
> not struct task_struct. This bug is involved by adding support to anonymous
> member modified by me...

Luckily it's a relatively rare scenario, and in this particular case,
"task -R fs" still works...

Queued for crash-6.1.7.

Thanks,
  Dave