input: atmel_mxt_ts: add DoubleTap2Wake support

This allows to wake the device with a simple double tap on the screen.
board-latona-mux: allow to use the touchscreen as wakeup source

Required by DoubleTap2Wake.
latona defconfigs: enable DoubleTap2Wake
Merge branch 'latona-3.0' into latona-3.0.y