clk: rockchip: fix the gate bit for i2c4 and i2c8 on rk3399

The gate bits of the i2c4 and i2c8 are incorrect due to the manual
error, we need to fix them.

Signed-off-by: Xing Zheng <zhengxing@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>