i2c: rk3x: add support for rk3228

Enable the I2C core for this SoC.

Signed-off-by: Yakir Yang <ykk@rock-chips.com>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>