x86, mcheck: Avoid duplicate sysfs links/files for thresholding banks

kobject_add_internal failed for threshold_bank2 with -EEXIST,
don't try to register things with the same name in the same
directory:

  Pid: 1, comm: swapper Tainted: G        W  2.6.31 #1
  Call Trace:
  [<ffffffff81161b07>] ? kobject_add_internal+0x156/0x180
  [<ffffffff81161cc0>] ? kobject_add+0x66/0x6b
  [<ffffffff81161793>] ? kobject_init+0x42/0x82
  [<ffffffff81161cf9>] ? kobject_create_and_add+0x34/0x63
  [<ffffffff81393963>] ? threshold_create_bank+0x14f/0x259
  [<ffffffff8139310a>] ? mce_create_device+0x8d/0x1b8
  [<ffffffff81646497>] ? threshold_init_device+0x3f/0x80
  [<ffffffff81646458>] ? threshold_init_device+0x0/0x80
  [<ffffffff81009050>] ? do_one_initcall+0x4f/0x143
  [<ffffffff816413a0>] ? kernel_init+0x14c/0x1a2
  [<ffffffff8100c8da>] ? child_rip+0xa/0x20
  [<ffffffff81641254>] ? kernel_init+0x0/0x1a2
  [<ffffffff8100c8d0>] ? child_rip+0x0/0x20
  kobject_create_and_add: kobject_add error: -17

(Probably the for_each_cpu loop should be entirely removed.)

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
LKML-Reference: <20100827092006.GB5348@loge.amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>