ufs_vnops.c: use unsigned type for newparent inode number in ufs_rename()
Otherwise it is sign-extended into 64bit ino_t on the call to
ufs_dirrewrite(). This causes invalid inode number recorded in the SU
tracking structures (newdirem) and triggers corresponding panics.
Reviewed by: mckusick, olce
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D51573