Merge the UHID driver, backported from Linux 3.8.

The userspace HID driver is needed by the JB Bluetooth stack in order to process input from Bluetooth keyboards.

Change-Id: I48ae89323420b06d9d519697c79df33931ebef31
Credit: This is almost an identical copy of the @plaguedbypenguins work for @KonstaT fork of zte-kernel-msm7x27.
Ref: http://git.io/1cj9sQ