clocksource/drivers/rockchip: Add support for the rk3399 SoC

The only difference between the rk3399 SoC and the other ones is the control
register offset which is different.

Add a new field to store the control register address depending on the SoC
and use it instead of the <base> + <control offset>.

Signed-off-by: Huang Tao <huangtao@rock-chips.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Heiko Stuebner <heiko@sntech.de>
Tested-by: Jianqun Xu <jay.xu@rock-chips.com>
Signed-off-by: Caesar Wang <wxt@rock-chips.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>