ACPI: thinkpad-acpi: add explicit remark about missing sysfs attributes (v2)
The sysfs interface defines that if some functionality is not available,
the attribute should not be there at all. Add an explicit remark to remind
userland about this.
Hot key NVRAM polling control attributes, Bluetooth and Wireless control
attributes, and a few others are examples of attributes that will not exist
if the features they depend on are not available.
Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>