gpk: Replace assert with error
gpk: Replace assert with error

Thanks oss-fuzz

https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=28306

frankmorgner/OpenSC,dengert/OpenSC,hongquan/OpenSC-main,LudovicRousseau/OpenSC,fabled/OpenSC,mouse07410/OpenSC,dengert/OpenSC,LudovicRousseau/OpenSC,fabled/OpenSC,dengert/OpenSC,philipWendland/OpenSC,fabled/OpenSC,metsma/OpenSC,frankmorgner/OpenSC,Jakuje/OpenSC,philipWendland/OpenSC,Jakuje/OpenSC,hongquan/OpenSC-main,OpenSC/OpenSC,OpenSC/OpenSC,fabled/OpenSC,metsma/OpenSC,frankmorgner/OpenSC,metsma/OpenSC,Jakuje/OpenSC,hongquan/OpenSC-main,LudovicRousseau/OpenSC,philipWendland/OpenSC,mouse07410/OpenSC,OpenSC/OpenSC,frankmorgner/OpenSC,Jakuje/OpenSC,mouse07410/OpenSC