Log shipping can only be used against a database that has Full or Bulk-logged recovery. The recovery model for most of the system databases is Simple (see BOL - Recovery Models for System Databases).
It is a strange thing to want to do, and not really workable even if you could do Full backups of the Master and the other System databases. The Secondary database (where you are shipping to) is in a state of Restoring or suchlike, and I wouldn't like to try and start a server that had Master in that state.
What are you trying to achieve?