If we don't enable the Schmitt trigger on the 32 kHz clock then systems
won't always resume from suspend properly.  Presumably anything else in
the system that relies on the 32 kHz clock also will have problems
without the Schmitt trigger enabled.

Enable it always since having the 32 kHz clock on GPIO0_A0 isn't
exactly an optional feature, so all boards using rk3399 will need this.

Change-Id: Idc18c6cd1adc5be5f60efd9cb805d83d5cd40129