ARM: ux500: Add all known I2C sub-device nodes to the HREF DT

Here we add the skeleton nodes for each of the known I2C sub-devices
currently registered on ST-Ericsson's HREF Development Platform. We
will fill these nodes in turn as the drivers are enabled for Device
Tree.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>