Tanaro: Remove spread spectrum service as settings will be set by u-boot

Remove the systemd service that set the spread spectrum settings for the VideoPLL1 during startup from the linux userland as this was unreliable. The settings will be applied in u-boot already.

The spreadspectrum python script is still installed and can be used to verify the settings, as well as modifying them in a debug environment.

BCS 746-000332