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

This reverts commit ccb159eb0cde3345192deb9ab3f9ba4c4f7416ae.
cypress: report led status via sysfs

Change-Id: Iddecb0688e758eca3ba77b520510a6728ad1e3bb