Efinix rework primitives

[trabucayre]

This PR is not for merge directly: it is based on @Dolu1990 PR and only adds:

• clkout name is modified to integrate pll id/name
• ClkOutput now receives a ClkSignal instead of an str

Note:

• ClkInput remains unchanged: TODO
• during sdc merge lines must be filtered to remove create_clock from LiteX (avoid conflicts)