MFC 243152,255478: Two SOCK_SEQPACKET fixes:
- Update comment.
- Provide pr_ctloutput method for AF_LOCAL/SOCK_SEQPACKET sockets.
MFC r260110:

Eliminate unused drbr_stats_update implementation in oce(4) driver.

Noticed by:	dim
[automated] Merge in upstream-github/stable/9