ARM: dts: bcm28155-ap: Enable all the i2c busses

Enable all available i2c busses.

Signed-off-by: Tim Kryger <tim.kryger@linaro.org>
Reviewed-by: Christian Daudt <csd@broadcom.com>
Reviewed-by: Matt Porter <matt.porter@linaro.org>
Reviewed-by: Markus Mayer <markus.mayer@linaro.org>
Signed-off-by: Christian Daudt <bcm@fixthebug.org>