input: synaptics_dsx_2.6: add secure touch support for Synaptics V2.6

8953 QRD supports Synaptics touch controller. For synaptics_dsx_2.6 driver
to work with the TrustZone secure touch, all the touch interrupts must
be forwarded between the Linux Kernel and the TrustZone input driver.
Add APIs and configuration to support this.

CRs-Fixed: 990820
Change-Id: I47520f9ba91b7645dff2c11b4c58a0b7aeed2765
Signed-off-by: Shantanu Jain <shjain@codeaurora.org>