i2c/nuc900: add i2c driver support for nuc900

This patch is to add i2c driver support for nuc900.

Signed-off-by: Wan ZongShun <mcuos.com@gmail.org>
Reviewed-by: Marek Vasut <marek.vasut@gmail.com>
Reviewed-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>