mach-ux500: add U8500 UIB platform data

The U8500 UIB contains a Synaptics RMI touchpanel and
a matrix keyboard via the TC35893 port expander device.

Signed-off-by: Sundar Iyer <sundar.iyer@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>