uapi: hbtp_input: exposes first and last ABS_MT parameter

When user space sets multi-touch parameters on hbtp_input driver
through ioctl, it needs to know the total number of ABS_MT parameters
that are supported by kernel. Add two macros for the first and the
last ABS_MT parameter to expose to user space.

Change-Id: I68ad9dad77facf1d1efcfc9a3d69235b1094d369
Signed-off-by: Jing Lin <jinglin@codeaurora.org>