ARM: rockchip: set correct stabilization thresholds in suspend

Currently the stabilization thresholds for the oscillator and external pmu
are statically set to 30ms based on a 32kHz clock rate. This leaves out the
case when we don't switch to the 32kHz clock when only entering the shallow
suspend mode where the logic keeps running.

So, set the correct threshold after we have determined if we switch to the
32kHz clock or stay with the 24MHz one. Also set the oscillator-
stabilization to 0 if it is kept running during suspend, as it of course
does not need to stabilize then.

Reported-by: Chris Zhong <zyw@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Chris Zhong <zyw@rock-chips.com>
Tested-by: Chris Zhong <zyw@rock-chips.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>