Refactor TARGET_TAP_TO_WAKE_NODE

Add TARGET_POWER_SET_FEATURE_LIB, since other devices
are not simply writing a 0/1 to a device node.
TARGET_TAP_TO_WAKE_NODE is still valid and both
TARGET_TAP_TO_WAKE_NODE and TARGET_POWER_SET_FEATURE_LIB are
allowed to coexist. (Currently set_feature only has double tap
to wake, but it may be extended in future)

Change-Id: I5c6204fd38a6fbe48e8aac49843bfa047c4b6436
3 files changed