s2w/dt2w: Add power key toggle

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>

Conflicts:
	drivers/video/msm/mdss/mdss_dsi_panel.c

Change-Id: Icf059fbcbd53b660dd5ceec0cf39a9585df4293c
s2w/dt2w: Prevent touches during phone calls

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
Defconfig: enable PREVENT_SLEEP and PWRKEY_SUSPENDED

Change-Id: I7e0832a028df68601ce3347f3bb47313d22de8f0