Improved comment for proc_dp_verify_sync() for fractional sync periods.

libraries/base/dp/src/vhdl/dp_bsn_sync_scheduler.vhd

libraries/base/dp/tb/vhdl/tb_dp_bsn_source_v2.vhd

libraries/base/dp/tb/vhdl/tb_dp_bsn_sync_scheduler.vhd