MFC r362289:
When converting the static arrays to mallocarray() in r356621 I missed one place where we now need to multiply the size of the struct with the number of entries. This lead to problems when restarting user space daemons, as the cleanup was never properly done, resulting in MRT_ADD_VIF EADDRINUSE. Properly zero all array elements to avoid this problem.
PR: 246629, 206583