Revert "ipfilter: Avoid allocating a new ipf token when not needed"

malloc() outside of a write lock will reduce potential contention.

MFC after: 3 days

This reverts commit 7f5e3b9fa3d159b7f061b4d01a767cbe5d0527f3.

(cherry picked from commit cf9b6857545371ab5becc6a785c62bc844cb2f94)