input: touchscreen: synaptics_3200: Allow disabling keypad

Change-Id: I0882249f2ea84777db31bf9b887f8874b8c25d73
Initial T6_UL support

Status:
-Backlight delayed turning on
-No Audio (look for KERNEL PANIC comment in board-t6-audio.c)
-No Wifi
-No Front Cam
-Sensors?

Change-Id: Ie679eb05fde9197ffb9947f47e9343691c1b5ada