ARM: pxa: hx4700: Add Synaptics NavPoint touchpad

This patch adds the Synaptics NavPoint touchpad to the hx4700 platform:
1. Change GPIO23_SSP1_SCLK value in hx4700_pin_config[] from an output
to an input, since the NavPoint is connected to SSP in SPI slave mode.
2. Add GPIO102_GPIO (NavPoint power) to hx4700_pin_config[].
3. Add navpoint platform_device to devices[].

Signed-off-by: Paul Parsons <lost.distance@yahoo.com>
Cc: Philipp Zabel <philipp.zabel@gmail.com>
Signed-off-by: Haojian Zhuang <haojian.zhuang@gmail.com>