LEF should be written from MAG/GDS

[mbalestrini]

I'm getting some offset between the generated .lef and .gds
This happen in a design where there were no pins on the left side (not sure if that was the problem but I think it might be the cause)
The generated lef has an origin different than (0,0), but gds.tcl script aligns the design origin to (0,0)

I think it would be better to create the lef file after the mag/gds, as in the openlane flow (/openlane/scripts/magic/lef.tcl)

The other difference in .lef generation that I noticed (vs openlane) is that dffram doesn't use the lef write - hide option. Don't know if there's a reason behind that