input: synaptics: Add checks of user input data

Add checks of the user input count to avoid possible heap overflow

Bug: 30799828
Change-Id: I896492b18c4ace6565fb9edd5cbf51f363ce157b
Signed-off-by: chengengjia <chengjia4574@gmail.com>
Signed-off-by: Andrew Chant <achant@google.com>
Git-repo: https://android.googlesource.com/kernel/msm.git


Git-commit: f549796fb9da58586c5cfc31d07b243c87dcfbd5
Signed-off-by: Dennis Cagle <d-cagle@codeaurora.org>