clk: rockchip: add reset controller

All Rockchip SoCs at least down to the ARM9-based RK28xx include the reset-
controller for SoC peripherals in their clock controller.
While the older SoCs (ARM9 and Cortex-A8) use a regular scheme to change
register values, the Cortex-A9 SoCs use a hiword-mask making locking unecessary.
To be compatible with both schemes the reset controller takes a flag to
decide which scheme to use, similar to the other HIWORD_MASK flags used in the
clock framework.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Acked-By: Max Schwarz <max.schwarz@online.de>
Tested-By: Max Schwarz <max.schwarz@online.de>
Signed-off-by: Mike Turquette <mturquette@linaro.org>