wake_timeout: add sweep2wake header

Fixes a build error with the latest wake_timeout commits for kernels
without wake gestures.

drivers/input/touchscreen/doubletap2wake.c: In function
‘dt2w_doubletap2wake_dump’:
drivers/input/touchscreen/doubletap2wake.c:336:40: error: ‘s2w_switch’
undeclared (first use in this function)
if (scr_suspended && !dt2w_switch && !s2w_switch) {
                                        ^
drivers/input/touchscreen/doubletap2wake.c:336:40: note: each undeclared
identifier is reported only once for each function it appears in
drivers/input/touchscreen/doubletap2wake.c:337:3: error: implicit
declaration of function ‘wake_pwrtrigger’ [-Werror=implicit-function-
declaration]
   wake_pwrtrigger();
   ^