ITS code duplicated between NET and NCP.

[larsbrinkhoff]

If ITS is built with NCPP=1 and INETP=0, the following symbols are defined twice: NSTYNT, NSTYN0, NSTYN1, NSTYN2, NSTYN3, STYNTC, STYNT7, and STYNT8. They are duplicated in the NET and the NCP files.