ACPI: sysfs: Use __ATTR_RO() and __ATTR_RW() macros

We have a few open-coded __ATTR_RO() and __ATTR_RW() macros.
Replace the custom code with generic macros.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>