Document r267694, cxgbe(4) rx buffer recycling fix.

Sponsored by:	The FreeBSD Foundation
Document r267734, send-pr(1) replaced with stub pointing to
bugzilla.

Sponsored by:	The FreeBSD Foundation
Document r267747, patch(1) --dry-run alias.

Sponsored by:	The FreeBSD Foundation
Document r267771, sctp binding bug.

Sponsored by:	The FreeBSD Foundation
Document r267849, cxgbe(4) T4 and T5 firmwares update.
Add Chelsio vendor.ent entry.

Sponsored by:	The FreeBSD Foundation