arm: dts: owl-s500-roseapplepi: Add I2C pinctrl configuration

Add pinctrl definitions for the I2C controllers used in RoseapplePi SBC.
For the moment enable only I2C0, which is used by the ATC2603C PMIC.

Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@gmail.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>