rt/softpll_ng: track only lower half of the ports (speed reasons, FIXME), added shifter busy call, fixed PPS output enable in GM/FreeMaster modes

modules/wrsw_rt_subsystem: updated softpll with grandmaster mode, PPSgen instantiation inside RT subsys

rt/softpll: bugfixes: drive DAC to constant value when out-of-lock or master, ptracker channel order and phase range check fix

rt/dev/softpll: single entry point to rule them all (GM, master, slave modes), fully non-blocking operation