input: maxim_sti: move header to uapi

Move kernel data structures to driver and keep the
data structures shared between kernel and user space
in the header file. Move the header to uapi to make
it accesible to user space.

Fix checkpatch errors to replace deprecated functions
and hardcoded error return values.

Change-Id: Ic3312c11ddda9f02da9807a6243206d582281995
Signed-off-by: Jing Lin <jinglin@codeaurora.org>