platforms/drm: put double tap timer behind config option

This feature was implemented in commit a66eb1a5 earlier

Double tap wake up is not a feature to be implemented at compositor
level but rather at the hardware/kernel level. Double tap timer here
means when screen is turned off, libinput will continue to poll the
touchscreen for new events.

double-tap-to-wakeup is generally interrupt at driver/hardware level
which have ability to wake system up even from the sleep.

Provide a option to disable the double tap timer on kwin side for
devices which makes use of suspend since when in suspend kwin can not
wake device up, and that provides confusing user experience.