input: touchboost: add back keypad filtering. I removed it earlier because I didn't know what it was for, so it seems it is, in this device's case, volume up/down and power button.

Change-Id: I3ecfb74ab6728e2f962ec751b118c573fdf76c80
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>