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

This reverts commit ab5373cd624a34c126681f1a1864b49fd3b21a62.
Revert "cypress-touchkey : add sysfs interface to enable/disable lighting hardwarekey backlight on screen touch (Yank555.lu)"

This reverts commit aa6e024f02b199bd498f4b9f1954346acb5291a0.