hm2/stepgen.c: do not touch table pins if not allocated
hm2/stepgen.c: do not touch table pins if not allocated

this fixes a crash if the stepgen instance does not support Table mode.

strahlex/machinekit,strahlex/machinekit,ArcEye/MK-Qt5,mhaberler/machinekit,ArcEye/MK-Qt5,mhaberler/machinekit,ArcEye/MK-Qt5,strahlex/machinekit,mhaberler/machinekit,ArcEye/MK-Qt5,strahlex/machinekit,mhaberler/machinekit,strahlex/machinekit,mhaberler/machinekit,mhaberler/machinekit,ArcEye/MK-Qt5,strahlex/machinekit,strahlex/machinekit,mhaberler/machinekit,ArcEye/MK-Qt5,mhaberler/machinekit,ArcEye/MK-Qt5,ArcEye/MK-Qt5