cypress-touchkey : add sysfs interface to enable/disable lighting hardwarekey backlight on screen touch (Yank555.lu)

Signed-off-by: umberto1978 <ur.tecnotop@gmail.com>
cypress-touchkey : add sysfs interface to enable/disable lighting hardwarekey backlight on screen touch (Yank555.lu)

- prevent h/w keys to light up on late_resume as well if disabled

Signed-off-by: umberto1978 <ur.tecnotop@gmail.com>