fix an off-by-one error when counting IOPort instances
fix an off-by-one error when counting IOPort instances

cnc-club/linuxcnc,araisrobo/linuxcnc,araisrobo/machinekit,ikcalB/linuxcnc-mirror,ArcEye/MK-Qt5,kinsamanka/machinekit,bobvanderlinden/machinekit,jaguarcat79/ILC-with-LinuxCNC,unseenlaser/machinekit,ArcEye/machinekit-testing,mhaberler/machinekit,cdsteinkuehler/linuxcnc,kinsamanka/machinekit,unseenlaser/linuxcnc,kinsamanka/machinekit,ArcEye/MK-Qt5,aschiffler/linuxcnc,strahlex/machinekit,cnc-club/linuxcnc,ArcEye/MK-Qt5,ArcEye/MK-Qt5,aschiffler/linuxcnc,EqAfrica/machinekit,araisrobo/machinekit,ianmcmahon/linuxcnc-mirror,RunningLight/machinekit,cdsteinkuehler/linuxcnc,mhaberler/machinekit,araisrobo/linuxcnc,narogon/linuxcnc,mhaberler/machinekit,araisrobo/machinekit,ArcEye/machinekit-testing,ianmcmahon/linuxcnc-mirror,ArcEye/machinekit-testing,bmwiedemann/linuxcnc-mirror,ArcEye/machinekit-testing,kinsamanka/machinekit,strahlex/machinekit,bobvanderlinden/machinekit,araisrobo/machinekit,Cid427/machinekit,bobvanderlinden/machinekit,ikcalB/linuxcnc-mirror,RunningLight/machinekit,ianmcmahon/linuxcnc-mirror,araisrobo/linuxcnc,RunningLight/machinekit,jaguarcat79/ILC-with-LinuxCNC,aschiffler/linuxcnc,ArcEye/MK-Qt5,bobvanderlinden/machinekit,mhaberler/machinekit,bmwiedemann/linuxcnc-mirror,mhaberler/machinekit,ikcalB/linuxcnc-mirror,EqAfrica/machinekit,Cid427/machinekit,araisrobo/machinekit,kinsamanka/machinekit,unseenlaser/linuxcnc,ikcalB/linuxcnc-mirror,strahlex/machinekit,narogon/linuxcnc,ArcEye/MK-Qt5,unseenlaser/machinekit,unseenlaser/linuxcnc,unseenlaser/machinekit,narogon/linuxcnc,RunningLight/machinekit,ArcEye/MK-Qt5,araisrobo/machinekit,cnc-club/linuxcnc,bmwiedemann/linuxcnc-mirror,cdsteinkuehler/linuxcnc,unseenlaser/machinekit,cdsteinkuehler/linuxcnc,ArcEye/MK-Qt5,unseenlaser/linuxcnc,Cid427/machinekit,EqAfrica/machinekit,unseenlaser/linuxcnc,unseenlaser/machinekit,unseenlaser/machinekit,bmwiedemann/linuxcnc-mirror,bobvanderlinden/machinekit,unseenlaser/machinekit,strahlex/machinekit,araisrobo/machinekit,narogon/linuxcnc,EqAfrica/machinekit,strahlex/machinekit,ikcalB/linuxcnc-mirror,cdsteinkuehler/linuxcnc,narogon/linuxcnc,jaguarcat79/ILC-with-LinuxCNC,RunningLight/machinekit,strahlex/machinekit,mhaberler/machinekit,mhaberler/machinekit,kinsamanka/machinekit,cnc-club/linuxcnc,araisrobo/machinekit,cdsteinkuehler/MachineKit,EqAfrica/machinekit,Cid427/machinekit,bobvanderlinden/machinekit,kinsamanka/machinekit,Cid427/machinekit,cnc-club/linuxcnc,unseenlaser/machinekit,mhaberler/machinekit,jaguarcat79/ILC-with-LinuxCNC,Cid427/machinekit,bobvanderlinden/machinekit,ArcEye/machinekit-testing,bmwiedemann/linuxcnc-mirror,ArcEye/machinekit-testing,bmwiedemann/linuxcnc-mirror,ianmcmahon/linuxcnc-mirror,jaguarcat79/ILC-with-LinuxCNC,RunningLight/machinekit,aschiffler/linuxcnc,bmwiedemann/linuxcnc-mirror,ianmcmahon/linuxcnc-mirror,cdsteinkuehler/MachineKit,Cid427/machinekit,cdsteinkuehler/MachineKit,araisrobo/machinekit,cdsteinkuehler/MachineKit,ianmcmahon/linuxcnc-mirror,cnc-club/linuxcnc,strahlex/machinekit,ikcalB/linuxcnc-mirror,cnc-club/linuxcnc,cdsteinkuehler/linuxcnc,araisrobo/linuxcnc,ArcEye/machinekit-testing,RunningLight/machinekit,ArcEye/machinekit-testing,EqAfrica/machinekit,EqAfrica/machinekit,EqAfrica/machinekit,ianmcmahon/linuxcnc-mirror,Cid427/machinekit,cdsteinkuehler/MachineKit,bobvanderlinden/machinekit,ikcalB/linuxcnc-mirror,araisrobo/linuxcnc,aschiffler/linuxcnc,RunningLight/machinekit,kinsamanka/machinekit,cdsteinkuehler/MachineKit