ACPI: debugfs custom_method open to non-root

Currently we have:

  --w--w--w-. 1 root root 0 2010-11-11 14:56 /sys/kernel/debug/acpi/custom_method

which is just crazy. Change this to --w-------.

Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Cc: stable@kernel.org (for 2.6.36)
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>