genl: Make genl_unregister() a NOP if NULL pointer is passed
genl: Make genl_unregister() a NOP if NULL pointer is passed

kolyshkin/libnl,claudelee/libnl,tklauser/libnl,greearb/libnl-ct,greearb/libnl-ct,cfriedt/libnl,tgraf/libnl,chitranshi/libnl,UnicronNL/libnl3,HolyShitMan/libnl-1,tgraf/libnl,baloo/libnl,chitranshi/libnl,greearb/libnl-ct,vyos/libnl3,claudelee/libnl,vyos/libnl3,cfriedt/libnl,vyos/libnl3,vyos/libnl3,dsahern/libnl,socketpair/libnl,tklauser/libnl,mshirley/libnl,congwang/libnl,HolyShitMan/libnl-1,honsys/libnl,houstar/libnl,congwang/libnl,baloo/libnl,karlhiramoto/libnl,Distrotech/libnl,mshirley/libnl,karlhiramoto/libnl,baloo/libnl,houstar/libnl,socketpair/libnl,HolyShitMan/libnl-1,cyclops8456/libnl3,teto/libnl_old,karlhiramoto/libnl,houstar/libnl,dsahern/libnl,UnicronNL/libnl3,honsys/libnl,teto/libnl_old,honsys/libnl,dsahern/libnl,baloo/libnl,tgraf/libnl,claudelee/libnl,tklauser/libnl,cyclops8456/libnl3,thom311/libnl,claudelee/libnl,houstar/libnl,mshirley/libnl,dsahern/libnl,cyclops8456/libnl3,cyclops8456/libnl3,teto/libnl_old,tgraf/libnl,chitranshi/libnl,cfriedt/libnl,tklauser/libnl,HolyShitMan/libnl-1,mshirley/libnl,kolyshkin/libnl,karlhiramoto/libnl,UnicronNL/libnl3,congwang/libnl,Distrotech/libnl,teto/libnl_old,socketpair/libnl,thom311/libnl,thom311/libnl,UnicronNL/libnl3,congwang/libnl,kolyshkin/libnl,Distrotech/libnl,kolyshkin/libnl,Distrotech/libnl,cfriedt/libnl,chitranshi/libnl,honsys/libnl