mm/memory-failure: remove obsolete comment in kill_proc()

mm/memory-failure: remove obsolete comment in kill_proc()

When user sets SIGBUS to SIG_IGN, it won't cause loop now.  For action
required mce error, SIGBUS cannot be blocked.  Also when a hwpoisoned page
is re-accessed, kill_accessing_process() will be called to kill the
process.

Link: https://lkml.kernel.org/r/20240612071835.157004-13-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>