ACPI: add ACPI debug attribute in sysfs

Add ACPI debug attributes in sysfs.
/proc/acpi/debug_layer && debug_level are deprecated by
/sys/module/acpi/parameters/debug_layer && debug_level.

NOTE: The operations to them are quite the same.
E.g. if you want to enable ACPI_DB_INFO, ACPI_DB_WARN,
 ACPI_DB_ERROR and disable the others,
#echo 0x13 >/sys/module/acpi/parameters/debug_level is OK,
and a boot option "acpi.debug_level = 0x13" also works.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>