scconf: Fix check for buffer size
scconf: Fix check for buffer size

buf_addch() store values on bp->bufcur and bp->bufcur + 1
but check size of the buffer only for bp->bufcur.

fabled/OpenSC,dengert/OpenSC,metsma/OpenSC,philipWendland/OpenSC,LudovicRousseau/OpenSC,fabled/OpenSC,OpenSC/OpenSC,LudovicRousseau/OpenSC,OpenSC/OpenSC,fabled/OpenSC,mouse07410/OpenSC,LudovicRousseau/OpenSC,OpenSC/OpenSC,metsma/OpenSC,mouse07410/OpenSC,philipWendland/OpenSC,dengert/OpenSC,mouse07410/OpenSC,fabled/OpenSC,dengert/OpenSC,metsma/OpenSC,philipWendland/OpenSC