ARM: sun4i: cubieboard: Enable the i2c controllers

The Cubieboard makes use of the first two i2c controllers found on the
Allwinner A10; i2c-0 is used internally for the PMIC, while i2c-1
is exposed on the board headers. This patch enables them in the device
tree.

Signed-off-by: Emilio López <emilio@elopez.com.ar>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Reviewed-by: Tomasz Figa <tomasz.figa@gmail.com>