If you're annoyed by entering the password each time you connect, you should consider setting up SSH keys. This will keep your device secured without breaking your development workflow.
If you really want to delete root password, you need to log in, open a terminal, and use the
passwd -d root command.
But please keep in mind security settings the day you'll start shipping hardware on the field: root account without password just allows anyone with a physical access to your device to do anything with it.