cyttsp-i2c-qc: Set input property bit to indicate a direct input device

Prop bit is checked in userspace and must be set in
driver in order to be recognized correctly, since it defaults
to mouse pointer.

Change-Id: Ibc3ce400033af171b60821c2945596676107eb75
Signed-off-by: Jessica Gonzalez <jgaona@codeaurora.org>