FROMLIST: clk: adjust clocks to their requested rate after parent changes

FROMLIST: clk: adjust clocks to their requested rate after parent changes

Given a hirarchy of clk1 -> [div] -> clk2, when the rate of clk1 gets
changed, clk2 changes as well as the divider stays the same. There may
be cases where a user of clk2 needs it at a specific rate, so clk2
needs to be readjusted for the changed rate of clk1.

So if a rate was requested for the clock, and its rate changed during
the underlying rate-change, with this change the clock framework now
tries to readjust the rate back to/near the requested one.

The whole process is protected by a new clock-flag to not force this
behaviour change onto every clock defined in the ccf.

(am from https://patchwork.kernel.org/patch/8993761/)

Change-Id: Ie2636710cb4e66815ee45b28ec86eeaaa47c55c7
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Xing Zheng <zhengxing@rock-chips.com>