Changes to lpf constraint file (correcting paths)

Changes to lpf constraint file (correcting paths)
Currently trying to get timing closure in CLK_GPLL_RIGHT.
For unknown reasons the compiler claims that this is NOT located on a dedicated clock-site and therefor get's excessive delay.
According to "LatticeECP3 sysCLOCK PLL/DLL Design and Usage Guide" page 10-38, Table 10-17, it is a preferred pad for feedback to the PLL.

Synthesys is complaining about undeclared clocks. Added soda_source_synconstraints.fdc. No success yet