fix a bug unloading hostmot2 when using tp_pwmgen
fix a bug unloading hostmot2 when using tp_pwmgen

tp_pwmgen uses a mixture of kernel memory and hal memory.  The "instance"
member is hal memory, from hal_malloc(), and the tp_pwmgen driver
erroneously called kfree() on it, causing the kernel memory manager to
freak out.

This commit removes the kfree(instance).  hal_malloc() has no matching
hal_free(), hal memory is simply reaped automatically when it unloads.

Thanks to Andy Pugh for the bug report and testing.

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