libsm: fixed out of bounds write
libsm: fixed out of bounds write

`sm_incr_ssc` performed an out of bounds write when `ssc` is bigger than
255. The local variable `ii` needs to be decremented instead of
incremented in the `for`-loop.

This was introduced in d30cd83a, wheras The previous implementation did
actually decrement `ii`, see d30cd83ad4b62f2d158cc7b61fa0022afc5d0af2

Fixes https://github.com/OpenSC/OpenSC/issues/785

jpki/OpenSC,rickyepoderi/OpenSC,Jakuje/OpenSC,viktorTarasov/OpenSC-SM,jpki/OpenSC,rickyepoderi/OpenSC,fabled/OpenSC,AktivCo/OpenSC,dengert/OpenSC,mouse07410/OpenSC,frankmorgner/OpenSC,OpenSC/OpenSC,frankmorgner/OpenSC,mtrojnar/OpenSC,philipWendland/OpenSC,hhonkanen/OpenSC,dengert/OpenSC,hongquan/OpenSC-main,viktorTarasov/OpenSC-SM,AktivCo/OpenSC,metsma/OpenSC,hhonkanen/OpenSC,Jakuje/OpenSC,philipWendland/OpenSC,viktorTarasov/OpenSC-SM,mouse07410/OpenSC,frankmorgner/OpenSC,fabled/OpenSC,hhonkanen/OpenSC,martinpaljak/OpenSC,hongquan/OpenSC-main,martinpaljak/OpenSC,LudovicRousseau/OpenSC,LudovicRousseau/OpenSC,frankmorgner/OpenSC,OpenSC/OpenSC,dengert/OpenSC,Jakuje/OpenSC,martinpaljak/OpenSC,hongquan/OpenSC-main,LudovicRousseau/OpenSC,mtrojnar/OpenSC,CardContact/OpenSC,AktivCo/OpenSC,metsma/OpenSC,CardContact/OpenSC,OpenSC/OpenSC,metsma/OpenSC,Jakuje/OpenSC,fabled/OpenSC,philipWendland/OpenSC,nmav/OpenSC,CardContact/OpenSC,fabled/OpenSC,rickyepoderi/OpenSC,nmav/OpenSC,nmav/OpenSC,mouse07410/OpenSC,jpki/OpenSC,mtrojnar/OpenSC