remove check for 6 or 12 parameters set

I misinterpreted the SLHA standard.  The logic should be the following:

 1. The user choses a GUT boundary condition (for example sugra)

 2. If no soft NMSSM parameters are set in EXTPAR, then we use msugra.
    Otherwise we use an extended sugra bc, where the set (soft)
    parameter is set to the given value.