Add missing sysctls for tuning vdev queue depths for new I/O types

This connects new tunables that were added but not exposed in:
r329502 (zpool remove)
r337007 (zpool initialize)

Reviewed by: avg
Approved by: re (kib)
MFC after: 2 weeks
Sponsored by: Klara Systems
Differential Revision: https://reviews.freebsd.org/D17494